This chapter also provides the hardware and software required to create ZFS file systems. Pentium. SPARC64.com/bigadmin/hcl.
How This Book Is Organized
The following table describes the chapters in this book. “Oracle Solaris ZFS File System (Introduction)” Chapter 2.
Chapter Description
Chapter 1. AMD64.
Note – This Oracle Solaris release supports systems that use the SPARC and x86 families of
processor architectures: UltraSPARC. This document cites any implementation differences between the platform types. For supported systems. see the Oracle Solaris Hardware Compatibility List. and Xeon EM64T. Experience using the Oracle Solaris operating system (OS) or another UNIX version is recommended. “Getting Started With Oracle Solaris ZFS”
Provides an overview of ZFS and its features and benefits. It also covers some basic concepts and terminology.Preface
The Oracle Solaris ZFS Administration Guide provides information about setting up and managing Oracle Solaris ZFS file systems. The supported systems appear in the Oracle Solaris Hardware Compatibility List at http://www.
Who Should Use This Book
This guide is intended for anyone who is interested in setting up and managing Oracle Solaris ZFS file systems. This guide contains information for both SPARC based and x86 based systems. Provides step-by-step instructions on setting up basic ZFS configurations with basic pools and file systems.sun.
13
.

using ZFS on an Oracle Advanced Topics” Solaris system with zones installed. “Oracle Solaris ZFS Provides information about using ZFS volumes. “Managing Oracle Solaris ZFS Storage Pools” Chapter 5. and using alternate root pools. and automatic mount point management and share interactions. “Working With Oracle Solaris ZFS Snapshots and Clones” Chapter 8.
Chapter 10. “Oracle Solaris ZFS and Traditional File System Differences” Chapter 4. Chapter 11. Provides detailed information about managing ZFS file systems. “Oracle Solaris ZFS Describes how to identify ZFS failures and how to recover from them. “Using ACLs and Attributes to Protect Oracle Solaris ZFS Files” Chapter 9. Provides a detailed description of how to create and administer ZFS storage pools. Describes how to manage ZFS root pool components. Included are such concepts as the hierarchical file system layout. such as configuring a mirrored root pool. property inheritance. upgrading your ZFS boot environments. “Managing ZFS Root Pool Components” Chapter 6.
Related Books
Related information about general Oracle Solaris system administration topics can be found in the following books:
■ ■ ■ ■
System Administration Guide: Common System Management Tasks System Administration Guide: Advanced Administration System Administration Guide: Devices and File Systems System Administration Guide: Security Services
14
Oracle Solaris ZFS Administration Guide • January 2011
. features of each version. “Oracle Solaris ZFS Version Descriptions” Describes available ZFS versions. “Oracle Solaris ZFS Delegated Administration”
Identifies important features that make ZFS significantly different from traditional file systems. Describes how to use ZFS delegated administration to allow nonprivileged users to perform ZFS administration tasks. Describes how to create and administer ZFS snapshots and clones. “Managing Oracle Solaris ZFS File Systems” Chapter 7.Preface
Chapter
Description
Chapter 3.
Describes how to use access control lists (ACLs) to protect your ZFS files by providing more granular permissions than the standard UNIX permissions. and the Solaris OS that provides the ZFS version and feature. Understanding these key differences will help reduce confusion when you use traditional tools to interact with ZFS. Recovery” Appendix A. and resizing swap and dump devices. Steps Troubleshooting and Pool for preventing failures are covered as well.

For example:
$ zfs diff tank/cindys@0913 tank/cindys@0914 M /tank/cindys/ + /tank/cindys/fileB
Chapter 1 • Oracle Solaris ZFS File System (Introduction) 19
.
ZFS Snapshot Differences (zfs diff)
Oracle Solaris 11 Express.
# zfs create -o encryption=on tank/cindys Enter passphrase for ’tank/cindys’: xxx Enter again: xxx
An encryption policy is set when a ZFS dataset is created. see “Encrypting ZFS File Systems” on page 187. which must be a minimum of 8 characters in length. the following two snapshots are created:
$ ls /tank/cindys fileA $ zfs snapshot tank/cindys@0913 $ ls /tank/cindys fileA fileB $ zfs snapshot tank/cindys@0914
Identify the snapshot differences.
ZFS Send Stream Enhancements
Oracle Solaris 11 Express. These enhancements provide flexibility in applying file system properties in a send stream to the receiving file system or in determining whether the local file system properties should be ignored when received. A dataset's encryption policy is inherited by descendent file systems and cannot be removed. such as a mountpoint property value. build 149: In this Solaris release. For more information. For example. you can set file system properties that are sent and received in a snapshot stream. build 148: In this Solaris release. The default encryption policy is to prompt for a passphrase. see “Applying Different Property Values to a ZFS Snapshot Stream” on page 210. build 147: In this Solaris release. you can encrypt a ZFS file system.What's New in ZFS?
ZFS File System Encryption
Oracle Solaris 11 Express. the tank/cindys file system is created with the encryption property enabled. you can determine ZFS snapshot differences by using the zfs diff command. For example. For more information.

For example:
# zfs set sync=always tank/perrin
The zil_disable parameter is no longer available in Solaris releases that include the sync property. Additional space is consumed by mirrored metadata. This is a performance enhancement only.
ZFS Storage Pool Recovery and Performance Enhancements
Oracle Solaris 11 Express. will have some latency-sensitive metadata automatically mirrored to improve read I/O throughput performance. the M indicates that the directory has been modified. If a damaged pool can not be accessed because the underlying devices are damaged. similar to what a mirrored storage pool provides.
■
■
Tuning ZFS Synchronous Behavior
Oracle Solaris 11 Express. Applications that depend on synchronous support might be impacted and data loss could occur.What's New in ZFS?
In the above output. This feature is primarily for pool recovery. or raidz3) storage pool. The property can be set before or after the dataset is created. see “Identifying ZFS Snapshot Differences (zfs diff)” on page 201. The default synchronous behavior is to write all synchronous file system transactions to the intent log and to flush all devices to ensure the data is stable. you can import the pool read-only to recover the data. created in this release and upgraded to at least pool version 29. see “Importing a Pool With a Missing Log Device” on page 119. Disabling the default synchronous behavior is not recommended. For existing RAIDZ pools that are upgraded to at least pool version 29. For more information. and it takes effect immediately. build 146 and build 147: In this Solaris release. You can import a pool in read-only mode. build 140: In this Solaris release.
20 Oracle Solaris ZFS Administration Guide • January 2011
. some metadata will be mirrored for all newly written data. For more information. see “Importing a Pool in Read-Only Mode” on page 121. For more information. A RAIDZ (raidz1. Mirrored metadata in a RAIDZ pool does not provide additional protection against hardware failures. The + indicates that fileB exists in the later snapshot. the following new ZFS storage pool features are provided:
■
You can import a pool with a missing log by using the zpool import -m command. raidz2. but the RAIDZ protection remains the same as previous releases. you can determine a ZFS file system's synchronous behavior by using the sync property.

the permissions are modified as necessary to enforce the file creation mode. 0755. then those permissions are included in the permission mode computation.1 -rw-r--r-. 0060 and so on.1 root root 206674 Jun 14 10:54 file. An existing ACL is discarded during chmod(2) operations by default. require deny ACEs. For example:
# ls -v file. but modes. A new permission mode calculation rule means that if an ACL has a user ACE that is also the file owner. The same rule applies if a group ACE is the group owner of the file.1 0:owner@:execute:deny 1:owner@:read_data/write_data/append_data/write_xattr/write_attributes /write_acl/write_owner:allow 2:group@:write_data/append_data/execute:deny 3:group@:read_data:allow 4:everyone@:write_data/append_data/write_xattr/execute/write_attributes /write_acl/write_owner:deny 5:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize :allow
The new behavior for a trivial ACL like 644 does not include the deny ACEs. 0664 do not need deny ACEs. The aclinherit property behavior includes a reduction of permissions when the property is set to restricted. This change means that the ZFS aclmode property is no longer available. build 139: In this Solaris release. Instead.1 root root 206663 Jun 14 11:52 file.What's New in ZFS?
c2t4d0 mirror-1 c2t7d0 c2t8d0
ONLINE ONLINE ONLINE ONLINE
0 0 0 0
0 0 0 0
0 0 0 0 (resilvering)
errors: No known data errors
ZFS ACL Interoperability Improvements
Oracle Solaris 11 Express. the following ACL improvements are provided:
■
Trivial ACLs do not require deny ACEs except for unusual permissions.1 -rw-r--r-. The old behavior includes deny ACEs in a trivial ACL like 644. For example. which means ACLs are no longer split into multiple ACEs during inheritance.
■
■
■
22
Oracle Solaris ZFS Administration Guide • January 2011
. For example:
# ls -v file. such as 0705.1 0:owner@:read_data/write_data/append_data/read_xattr/write_xattr /read_attributes/write_attributes/read_acl/write_acl/write_owner /synchronize:allow 1:group@:read_data/read_xattr/read_attributes/read_acl/synchronize:allow 2:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize :allow
■
ACLs are no longer split into multiple ACEs during inheritance to try to preserve the original unmodified permission. a mode of 0644.

ZFS Deduplication Property
Oracle Solaris 11 Express. build 140: In this Solaris release.
New ZFS System Process
Oracle Solaris 11 Express. see SDC(7). duplicate data blocks are removed synchronously. The threads in this process are the pool's I/O processing threads to handle I/O tasks. For more information. These processes are only available in the global zone. which detaches a disk or disks in the original mirrored pool to create another identical pool. For more information. If a file system has the dedup property enabled. The purpose of this process is to provide visibility into each storage pool's CPU utilization. For more information.
Solaris iSCSI Changes
Oracle Solaris 11 Express. zpool-poolname. see “Using a ZFS Volume as a Solaris iSCSI LUN” on page 254.What's New in ZFS?
For more information. such as compression and checksumming. see Chapter 8. This also means that the shareiscsi property that was used to share a ZFS volume as an iSCSI LUN is no longer available. build 136: In this Solaris release. Use the sbdadm command to configure and share a ZFS volume as an iSCSI LUN. you can use the deduplication property to remove redundant data from your ZFS file systems. see “Creating a New Pool By Splitting a Mirrored ZFS Storage Pool” on page 89. the Solaris iSCSI target daemon is replaced by using the COMSTAR target daemon. The result is that only unique data is stored and common components are shared between files. you can use the zpool split command to split a mirrored storage pool. build 129: In this Solaris release. build 128: In this Solaris release. You can enable this property as follows:
# zfs set dedup=on tank/home
Chapter 1 • Oracle Solaris ZFS File System (Introduction) 23
. each ZFS storage pool has an associated process. “Using ACLs and Attributes to Protect Oracle Solaris ZFS Files. that are associated with the pool. Information about these process can be reviewed by using the ps and prstat commands.”
Splitting a Mirrored ZFS Storage Pool (zpool split)
Oracle Solaris 11 Express.

For more information. For more information setting the deduplication property. or if more than the supported number of
24 Oracle Solaris ZFS Administration Guide • January 2011
.8G CAP DEDUP HEALTH ALTROOT 40% 2. For more information.opensolaris.What's New in ZFS?
Although deduplication is set as a file system property. the scope is pool-wide. The ALLOC field identifies the amount of physical space allocated to all datasets and internal metadata. For example. For example:
# zpool list tank NAME SIZE ALLOC FREE tank 136G 55. Do not enable the dedup property on file systems on production systems until you review the following considerations:
■ ■ ■
Determine if your data would benefit from deduplication space savings Determine whether your system has enough physical memory to support deduplication Known issues exist when attempting to remove a large dataset or destroying a large snapshot with deduplicated data
For more information about these considerations. build 128: In this Solaris release. you can identify the deduplication ratio as follows:
# zpool list tank NAME SIZE ALLOC FREE tank 136G 55. see “Changes to the zpool list Command” on page 24. see “The dedup Property” on page 163. a power failure occurs. build 128: A storage pool can become damaged if underlying devices become unavailable.2G 80.8G CAP HEALTH ALTROOT 40% ONLINE -
The previous USED and AVAIL fields have been replaced with ALLOC and FREE.org/bin/view/Community+Group+zfs/dedup
Changes to the zpool list Command
Oracle Solaris 11 Express. The FREE field identifies the amount of unallocated space in the pool.30x ONLINE -
The zpool list output has been updated to support the deduplication property. the zpool list output has changed to provide better space allocation information.2G 80.
ZFS Storage Pool Recovery
Oracle Solaris 11 Express. see “Displaying Information About ZFS Storage Pools” on page 105. see this FAQ: http://hub.

What's New in ZFS?
devices fail in a redundant ZFS configuration. Using the logbias=throughput value might improve performance for writing database files. Log device removal – You can now remove a log device from a ZFS storage pool by using the zpool remove command. This release provides new command features for recovering your damaged storage pool. two. Instead. A single log device can be removed by specifying the device name. three device failures can be sustained respectively. zpool clear. if any. However. build 120: In this Solaris release. For more information. In addition. Both the zpool clear and zpool import commands support the -F option to possibly recover a damaged pool. see “Repairing ZFS Storage Pool-Wide Damage” on page 286. to handle the requests at low latency. Redundant top-level virtual devices are now identified with a numeric identifier. or zpool import command automatically report a damaged pool and these commands describe how to recover the pool. a redundant RAID-Z configuration can now have either single-. the top level virtual device is mirror-0. ZFS uses the pool's separate log devices. double-. see Example 4–3. The default value is latency. If logbias is set to latency. For more information.
ZFS Log Device Enhancements
Oracle Solaris 11 Express.
Chapter 1 • Oracle Solaris ZFS File System (Introduction) 25
. which means that one. You can specify the raidz3 keyword for a triple-parity RAID-Z configuration. builds 122–125: The following log device enhancements are available:
■
The logbias property – You can use this property to provide a hint to ZFS about handling synchronous requests for a specific dataset. For more information. ZIL transaction records are written to the main pool. without any data loss. running the zpool status. When a separate log device is removed from the system. If logbias is set to throughput. A mirrored log device can be removed by specifying the top-level mirror for the log. or triple-parity. ZFS optimizes synchronous operations for global pool throughput and efficient use of resources.
■
Triple Parity RAIDZ (raidz3)
Oracle Solaris 11 Express. using this recovery feature means that the last few transactions that occurred prior to the pool outage might be lost. For example. the default value is recommended. ZFS does not use the pool's separate log devices. in a mirrored storage pool of two disks. For most configurations. see “Creating a RAID-Z Storage Pool” on page 75.

you might consider using the snapshots hold feature in this Solaris release. on tank/home/cindys/snap@1. In addition. automatic LUN expansion is enabled on the tank pool. ZFS has been enhanced to recognize these events and adjusts the pool based on the new size of the expanded LUN. you can reset the autoexpand property after the LUN is attached or made available by using the zpool replace feature. You can hold a snapshot or set of snapshots.
# zpool create -o autoexpand=on tank c1t13d0
The autoexpand property is disabled by default so you can decide whether you want the LUN expanded or not. but the pool size is not expanded until the autoexpand property is enabled. you can create the pool with the autoexpand property enabled. For example.
26 Oracle Solaris ZFS Administration Guide • January 2011
. see “Holding ZFS Snapshots” on page 197. A LUN can also be expanded by using the zpool online -e command. build 120: In this Solaris release.
ZFS Device Replacement Enhancements
Oracle Solaris 11 Express. build 120: If you implement different automatic snapshot policies so that older snapshots are being inadvertently destroyed by zfs receive because they no longer exist on the sending side. For example. keep. For example:
# zpool online -e tank c1t6d0
Or. the following syntax puts a hold tag. These features enable you to expand a LUN and the resulting pool can access the expanded space without having to export and import pool or reboot the system. this feature allows a snapshot with clones to be deleted pending the removal of the last clone by using the zfs destroy -d command. You can use the autoexpand pool property to enable or disable automatic pool expansion when a dynamic LUN expansion event is received. depending on the setting of the autoexpand property.What's New in ZFS?
Holding ZFS Snapshots
Oracle Solaris 11 Express. a system event or sysevent is provided when an underlying device is expanded. the following pool is created with one 8-GB disk (c0t0d0).
# zpool set autoexpand=on tank
Or. The 8-GB disk is replaced with a 16-GB disk (c1t13d0).
# zfs hold keep tank/home/cindys@snap1
For more information. Holding a snapshot prevents it from being destroyed. For example.

ZFS User and Group Quotas
Oracle Solaris 11 Express.5K 16.5K 8. As described above.44G 0% ONLINE # zpool set autoexpand=on pool # zpool list NAME SIZE ALLOC FREE CAP HEALTH pool 16. In this release. you could apply quotas and reservations to ZFS file systems to manage and reserve disk space.
■
For more information about replacing devices.44G 76. ZFS was not able to replace an existing disk with another disk or attach a disk if the replacement disk was a slightly different size.44G 0% ONLINE # zpool online -e tank c1t13d0 # zpool list tank NAME SIZE ALLOC FREE CAP HEALTH tank 16.8G 90K 16. you can enable the autoexpand property or use the zpool online -e command to expand the full size of a LUN. For example:
# zpool create tank c0t0d0 # zpool list tank NAME SIZE ALLOC FREE CAP HEALTH tank 8. In this Solaris release. is to use the zpool online -e command even though the device is already online. you can replace an existing disk with another disk or attach a new disk that is nominally the same size provided that the pool is not already full.5K 8.44G 0% ONLINE # zpool replace pool c0t0d0 c1t13d0 # zpool list NAME SIZE ALLOC FREE CAP HEALTH pool 8.8G 0% ONLINE
ALTROOT ALTROOT ALTROOT -
Another way to expand the LUN in the above example without enabling the autoexpand property.44G 91.44G 0% ONLINE # zpool replace tank c0t0d0 c1t13d0 # zpool list tank NAME SIZE ALLOC FREE CAP HEALTH tank 8.
Chapter 1 • Oracle Solaris ZFS File System (Introduction) 27
.5K 8. you can set a quota on the amount of disk space consumed by files that are owned by a particular user or group. build 120: In previous Solaris releases.5K 8. you do not need to reboot the system or export and import a pool to expand a LUN.8G 91. see “Replacing Devices in a Storage Pool” on page 94. You might consider setting user and group quotas in an environment with a large number of users or groups.44G 76. In this release.44G 91.What's New in ZFS?
# zpool create pool c0t0d0 # zpool list NAME SIZE ALLOC FREE CAP HEALTH pool 8.8G 0% ONLINE
ALTROOT ALTROOT ALTROOT -
Additional device replacement enhancements in this release include the following features:
■
In previous releases.

you can set the aclinherit mode to pass the execute permission to the inherited ACL. build 120: In previous Solaris releases. use the zfs groupquota property.What's New in ZFS?
You can set a user quota by using the zfs userquota property. If the inherited ACL does not
28 Oracle Solaris ZFS Administration Guide • January 2011
. see “Setting ZFS Quotas and Reservations” on page 181. In this release.
ZFS ACL Pass Through Inheritance for Execute Permission
Oracle Solaris 11 Express. If aclinherit=passthrough-x is enabled on a ZFS dataset. A group's disk space usage can be viewed by using the groupused@group property. For example:
# zfs set userquota@user1=5G tank/data # zfs set groupquota@staff=10G tank/staff/admins
You can display a user's or a group's current quota setting as follows:
# zfs get userquota@user1 tank/data NAME PROPERTY VALUE SOURCE tank/data userquota@user1 5G local # zfs get groupquota@staff tank/staff/admins NAME PROPERTY VALUE tank/staff/admins groupquota@staff 10G
SOURCE local
Display general quota information as follows:
# zfs userspace tank/data TYPE NAME USED QUOTA POSIX User root 3K none POSIX User user1 0 5G # zfs groupspace tank/staff/admins TYPE NAME USED QUOTA POSIX Group root 3K none POSIX Group staff 0 10G
You can display an individual user's disk space usage by viewing the userused@user property. you can include execute permission for an output file that is generated from cc or gcc compiler tools. For example:
# zfs get userused@user1 tank/staff NAME PROPERTY VALUE tank/staff userused@user1 213M # zfs get groupused@staff tank/staff NAME PROPERTY VALUE tank/staff groupused@staff 213M SOURCE local SOURCE local
For more information about setting user quotas. you could apply ACL inheritance so that all files are created with 0664 or 0666 permissions. if you want to optionally include the execute bit from the file creation mode into the inherited ACL. To set a group quota.

see Example 8–13. including RECEIVED. The following example sends the
Chapter 1 • Oracle Solaris ZFS File System (Introduction) 29
. you might receive a stream with the compression property disabled. build 120: The following ZFS file system enhancements are included in these releases. the zfs inherit command masks the received value with the inherited value until issuing a zfs inherit -S command reverts it to the received value. You can use the zfs send -p option to include properties in the send stream without the -R option. ZFS Snapshot Stream Property Enhancements – You can set a received property that is different from its local property setting.
■
Setting ZFS Security Labels – The mlslabel property is a sensitivity label that determines if a dataset can be mounted in a Trusted Extensions labeled-zone. Or. New ZFS command options and properties to support send and local property values are as follows:
■
■
Use the zfs inherit -S to revert a local property value to the received value.
ZFS Property Enhancements
Oracle Solaris 11 Express. If the property does have a received value. The mlslabel property can be modified only when Trusted Extensions is enabled and only with the appropriate privilege. You can use the zfs get -o to include the new non-default RECEIVED column.What's New in ZFS?
include execute permission. you don't have to worry about the setting on the sending side replacing the received side value. but you want compression enabled in the receiving file system. Since the local value overrides the received value. then the executable output from the compiler won't be executable until you use the chmod command to change the file's permissions. For example. The zfs get command shows the effective value of the compression property under the VALUE column. If a property does not have a received value.
Automatic ZFS Snapshots
Oracle Solaris 11 Express. This means that the received stream has a received compression value of off and a local compression value of on. This tool automatically snapshots ZFS file systems and allows you to browse and recover snapshots of file systems. For more information. if any. see “Managing Automatic ZFS Snapshots” on page 202.
■
■
In addition. the behavior of the zfs inherit -S command is the same as the zfs inherit command without the -S option. For more information. you can use the zfs send -e option to use the last element of the sent snapshot name to determine the new snapshot name. use the zfs get -o all command to include all columns. The default is none. build 120: This release includes the Time Slider snapshot tool.

The properties are as follows:
■
usedbychildren – Identifies the amount of disk space that is used by children of this dataset. You must determine if setting cache properties is appropriate for your environment. compression is enabled on the ZFS file system that is created when the pool is created:
# zpool create -O compression=on pool mirror c0t1d0 c0t2d0
■
Setting cache properties on a ZFS file system – Two new ZFS file system properties enable you to control what is cached in the primary cache (ARC) and the secondary cache (L2ARC). file systems. The default is all.
■
Viewing disk space accounting properties – New read-only file system properties help you identify disk space usage for clones. only new I/O is cache based on the values of these properties.
30
Oracle Solaris ZFS Administration Guide • January 2011
. and volumes. and snapshots. which would be freed if all the dataset's children were destroyed. If set to all. secondarycache – Controls what is cached in the L2ARC. In the following example. none. For example:
# zfs set primarycache=metadata tank/datab # zfs create -o primarycache=metadata tank/newdatab
When these properties are set on existing file systems. The property abbreviation is usedchild.What's New in ZFS?
poola/bee/cee@1 snapshot to the poold/eee file system and only uses the last element (cee@1) of the snapshot name to create the received file system and snapshot. Some database environments might benefit from not caching user data.
# zfs list -rt all poola NAME USED AVAIL REFER MOUNTPOINT poola 134K 134G 23K /poola poola/bee 44K 134G 23K /poola/bee poola/bee/cee 21K 134G 21K /poola/bee/cee poola/bee/cee@1 0 21K # zfs send -R poola/bee/cee@1 | zfs receive -e poold/eee # zfs list -rt all poold NAME USED AVAIL REFER MOUNTPOINT poold 134K 134G 23K /poold poold/eee 44K 134G 23K /poold/eee poold/eee/cee 21K 134G 21K /poold/eee/cee poold/eee/cee@1 0 21K ■
Setting ZFS file system properties at pool creation time – You can set ZFS file system properties when a storage pool is created. If set to none. neither user data nor metadata is cached.
You can set these properties on an existing file system or when a file system is created. Possible values for both properties – all. both user data and metadata are cached. and metadata. The cache properties are set as follows:
■ ■ ■
primarycache – Controls what is cached in the ARC. If set to metadata. only metadata is cached.

The property abbreviation is usedrefreserv.00G 0 0 38K 0 20K 0 18K 18K 0 18K 0 0 512M 0 111M 401M 0
The preceding command is equivalent to the zfs list -o name.4G rpool/export 25. You can use the zfs list -t snapshots command to display snapshot information. In particular.4G rpool/dump 25. For example:
# zpool get listsnapshots pool NAME PROPERTY VALUE SOURCE pool listsnapshots off default # zpool set listsnaps=on pool
Chapter 1 • Oracle Solaris ZFS File System (Introduction) 31
.usedrefreserv. set the listsnapshots property.used.
■
■
These new properties break down the value of the used property into the various elements that consume disk space. usedbysnapshots – Identifies the amount of disk space that is consumed by snapshots of this dataset.What's New in ZFS?
■
usedbydataset – Identifies the amount of disk space that is used by this dataset itself. which would be freed if the refreservation was removed. after first destroying any snapshots and removing any refreservation.usedchild -t filesystem.4G rpool/export/home 25. The property abbreviation is usedds.00G 0 1. The default value is off. which means snapshot information is not displayed by default. the value of the used property breaks down as follows:
used property = usedbychildren + usedbydataset + usedbyrefreservation + usedbysnapshots
You can view these properties by using the zfs list -o space command.4G rpool/ROOT/snv_98 25.29G 0 18K 0 6. For example:
# zfs list -t snapshot NAME USED AVAIL REFER MOUNTPOINT pool/home@today 16K 22K pool/home/user1@today 0 18K pool/home/user2@today 0 18K pool/home/user3@today 0 18K -
To display snapshot information by default.volume command.29G 6. which would be freed if the dataset was destroyed. because disk space can be shared by multiple snapshots.29G 0 6.avail.usedds.4G rpool/ROOT 25.usedsnap.8G USED USEDSNAP USEDDS USEDREFRESERV USEDCHILD 7.
■
Listing snapshots – The listsnapshots pool property controls whether snapshot information is displayed by the zfs list command. The property abbreviation is usedsnap. Note that this is not the sum of the snapshots' used properties.29G 0 0 1.79G 6. For example:
$ zfs list -o space NAME AVAIL rpool 25.79G 0 64K 0 7. which would be freed if all of this dataset's snapshots were destroyed.4G rpool/swap 25. usedbyrefreservation – Identifies the amount of disk space that is used by a refreservation set on this dataset.

build 120: In this release. the pool will operate in a degraded mode and the log records will be written to the main pool until the separate log device is replaced. write_attributes. when you create a pool. One or more cache devices can be specified when the pool is created. In this scenario. rather than apply different ACL permissions individually. read_xattr. build 120: This release provides the ability to apply NFSv4–style ACLs in sets. which are used to cache storage pool data. and write_xattr
These ACL sets are prefined and cannot be modified. Using cache devices provides the greatest performance improvement for random-read workloads of mostly static content. For more information about using ACL sets. Consider using mirrored log devices to avoid the log device failure scenario. you can clear the error with the zpool clear command. and read_acl write_set = write_data.
Using ZFS ACL Sets
Oracle Solaris 11 Express.What's New in ZFS?
To recover from this error without replacing the failed log device. see Example 8–5. For example:
# zpool create pool mirror c0t2d0 c0t4d0 cache c0t0d0 # zpool status pool pool: pool state: ONLINE scrub: none requested config: NAME pool mirror c0t2d0 c0t4d0 cache c0t0d0 STATE ONLINE ONLINE ONLINE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
errors: No known data errors
Chapter 1 • Oracle Solaris ZFS File System (Introduction) 33
.
Using Cache Devices in Your ZFS Storage Pool
Oracle Solaris 11 Express. The following ACL sets are provided:
■ ■ ■ ■
full_set = all permissions modify_set = all permissions except write_acl and write_owner read_set = read_data. read_attributes. append_data. you can specify cache devices. Cache devices provide an additional layer of caching between main memory and disk.

Capacity and reads can be monitored by using the zpool iostat command as follows:
# zpool iostat -v pool 5
Cache devices can be added or removed from a pool after the pool is created. the zfs rollback -f option is no longer needed to force an unmount operation. Thus.5K pool/fs@snapD 0 21K # zfs send -I pool/fs@snapA pool/fs@snapD > /snaps/fs@combo
This syntax sends all incremental snapshots between fs@snapA to fs@snapD to fs@combo. see Chapter 5.5K pool/fs@snapB 17K 20K pool/fs@snapC 17K .20. For example:
# zfs list NAME USED AVAIL REFER MOUNTPOINT pool 428K 16. Using this command. The -f option is no longer supported and is ignored. they gradually fill with content from main memory. For example:
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Oracle Solaris ZFS Administration Guide • January 2011
. if specified. build 120: This release enables you to roll back a dataset without unmounting it first. you can now perform the following tasks:
■
Send all incremental streams from one snapshot to a cumulative snapshot.
Enhancements to the zfs send Command
Oracle Solaris 11 Express. build 120: This Oracle Solaris release uses a ZFS root file system by default.5G 21K /pool/fs pool/fs@snapA 16K . see “Creating a ZFS Storage Pool With Cache Devices” on page 77 and Example 4–4.18. “Managing ZFS Root Pool Components.What's New in ZFS?
After cache devices are added. T he original snapshot must already exist on the receiving side to accept the incremental stream. For more information.
ZFS Root Pool Management
Oracle Solaris 11 Express. Depending on the size of your cache device. build 120: This release includes the following enhancements to the zfs send command.
■
Send an incremental stream from the original snapshot to create a clone. For more information about managing root pool components.”
Rolling Back a Dataset Without Unmounting
Oracle Solaris 11 Express. it could take over an hour for the device to fill.5G 20K /pool pool/fs 71K 16.

see Example 7–1. this release includes dataset quotas and reservations that do not include descendents. all properties. such as snapshots and clones. you can set a 20-GB quota that enables you to manage studentA's snapshots. such as snapshots and clones. For additional flexibility. # zfs receive -F pool/clone < /snaps/fsclonesnap-I
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Send a replication stream of all descendent file systems. see Example 7–1. see “Setting ZFS Quotas and Reservations” on page 181. not including its descendents. This hard limit does not include disk space used by descendents.What's New in ZFS?
# zfs send -I pool/fs@snap1 pool/clone@snapA > /snaps/fsclonesnap-I . you can set a 10-GB refquota limit for studentA that sets a 10-GB hard limit of referenced disk space.
■
Send an incremental replication stream. This product provides the ability to share files between Solaris and Windows or MacOS systems. and clones are preserved.
■
The refquota property enforces a hard limit on the amount of disk space that a dataset can consume.
# zfs set refquota=10g tank/studentA # zfs set quota=20g tank/studentA
For more information. For more information.
ZFS Quotas and Reservations for File System Data Only
Oracle Solaris 11 Express. build 120: In addition to the existing ZFS quota and reservation features. snapshots.
Chapter 1 • Oracle Solaris ZFS File System (Introduction) 35
. in the disk space accounting. The refreservation property sets the minimum amount of disk space that is guaranteed for a dataset.
ZFS File System Properties for the Solaris CIFS Service
Oracle Solaris 11 Express. up to the named snapshots. For example:
# zfs send -R pool/fs@snap > snaps/fs-R
For an extended example.
■
For example. descendent file systems. . For example:
# zfs send -R -[iI] @snapA pool/fs@snapD
For an extended example. When received. build 120: This release provides support for the Solaris Common Internet File System (CIFS) service. see “Sending and Receiving Complex ZFS Snapshot Streams” on page 211.

continue. or panic. The failmode property can be set to these values: wait. This release provides two properties. For most ZFS configurations. The following describes the new storage pool properties in this release:
■
The cachefile property – Oracle Solaris 11 Express. the sharesmb property is available to share ZFS files in the Solaris CIFS environment. The failmode property is set like other settable ZFS properties. All pools in the cache are automatically imported when the system boots. which can be set either before or after the pool is created. build 120: ZFS storage pool properties were introduced in an earlier release.
■
The failmode property – This property determines the behavior of a catastrophic pool failure due to a loss of device connectivity or the failure of all devices in the pool. For information about using the sharesmb property. and then clear the error with the zpool clear command. which means you must reconnect the device or replace a failed device. build 120 This property controls where pool configuration information is cached. cachefile and failmode. This property replaces the temporary property that was used to indicate that pool information should not be cached in previous Solaris releases. You can set this property to cache pool configuration in a different location that can be imported later by using the zpool import -c command. More ZFS CIFS-related properties will be available in an upcoming release. The default value is wait. this property would not be used.
ZFS Storage Pool Properties
Oracle Solaris 11 Express. the following new ZFS properties are provided:
■ ■ ■ ■ ■
Case sensitivity support (casesensitivity) Non-blocking mandatory locks (nbmand) SMB share support (sharesmb) Unicode normalization support (normalization) UTF-8 character set support (utf8only)
Currently. see “Sharing and Unsharing ZFS File Systems” on page 178. However. The cachefile property is not persistent and is not stored on disk. the vscan property is available for scanning ZFS files if you have a 3rd-party virus scanning engine.What's New in ZFS?
To facilitate sharing files between these systems by using the Solaris CIFS service. For example:
# zpool set failmode=continue tank # zpool get failmode tank NAME PROPERTY VALUE SOURCE tank failmode continue local
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Oracle Solaris ZFS Administration Guide • January 2011
. In addition to the ZFS properties added for supporting the Solaris CIFS software product. installation and clustering environments might require this information to be cached in a different location so that pools are not automatically imported.

For example. NFS and other applications can also use fsync() to ensure data stability. For more information. In this Solaris release. You can modify delegated administration with the pool's delegation property. and the application workload. By default. You can attach a log device to an existing log device to create a mirrored log device. You can set up a ZFS log device when the storage pool is created or after the pool is created. see Chapter 9. For preliminary performance information.What's New in ZFS?
ZFS Delegated Administration
Oracle Solaris 11 Express. For example:
# zpool get delegation users NAME PROPERTY VALUE SOURCE users delegation on default # zpool set delegation=off users # zpool get delegation users NAME PROPERTY VALUE SOURCE users delegation off local
By default. This operation is identical to attaching a device in a unmirrored storage pool. such as with NVRAM or a dedicated disk. databases often require their transactions to be on stable storage devices when returning from a system call. You can use the zfs allow and zfs unallow commands to delegate and remove permissions. you can grant fine-grained permissions to allow nonprivileged users to perform ZFS administration tasks. see this blog:
39
Chapter 1 • Oracle Solaris ZFS File System (Introduction)
. Better performance might be possible by using separate intent log devices in your ZFS storage pool. you can decide if you want the ZIL blocks to continue to be allocated from the main storage pool or from a separate log device. For examples of setting up log devices. see “Creating a ZFS Storage Pool With Log Devices” on page 76 and “Adding Devices to a Storage Pool” on page 82. the hardware configuration of the pool. the ZIL is allocated from blocks within the main storage pool. build 120: In this release. Consider the following points when determining whether setting up a ZFS log device is appropriate for your environment:
■
Any performance improvement seen by implementing a separate log device depends on the device type. “Oracle Solaris ZFS Delegated Administration. the delegation property is enabled.” and zfs(1M).
Setting Up Separate ZFS Log Devices
Oracle Solaris 11 Express. Log devices for the ZFS intent log are not related to database log files. build 120: The ZFS intent log (ZIL) is provided to satisfy POSIX requirements for synchronous transactions.

the operation completes successfully. Log blocks are freed when the log transaction (system call) is committed. For example. but RAID-Z is not supported for log devices. Log devices can be added. and exported as part of the larger storage pool. For example:
# zfs get mountpoint. The maximum size of a log device should be approximately 1/2 the size of physical memory because that is the maximum amount of potential in-play data that can be stored. Any additional properties are disabled for the intermediate dataset.sun.com/perrin/entry/slog_blog_or_blogging_on
■ ■
Log devices can be unreplicated or mirrored. The minimum size of a log device is the same as the minimum size of each device in a pool. removed. build 120: You can use the -p option with the zfs create.5G 18K /datab # zfs create -p -o compression=on datab/users/area51
If the intermediate dataset already exists during the create operation. In the following example. attached. zfs clone.compression NAME PROPERTY datab/users/area51 mountpoint datab/users/area51 compression datab/users/area51 VALUE SOURCE /datab/users/area51 default on local
The intermediate dataset is created with the default mount point. if a system has 16 GB of physical memory. consider a maximum log device size of 8 GB. which is 64 MB.
40 Oracle Solaris ZFS Administration Guide • January 2011
. ZFS datasets (users/area51) are created in the datab storage pool. if it doesn't already exist.
# zfs list NAME USED AVAIL REFER MOUNTPOINT datab 106K 16. detached. replaced. imported.
■
■
■
Creating Intermediate ZFS Datasets
Oracle Solaris 11 Express. The amount of in-play data that might be stored on a log device is relatively small. For example:
# zfs get mountpoint. see zfs(1M). and zfs rename commands to quickly create a non-existent intermediate dataset. storing log blocks reverts to the storage pool. Properties specified apply to the target dataset. If a separate log device is not mirrored and the device that contains the log fails. not to the intermediate dataset.What's New in ZFS?
http://blogs.compression datab/users NAME PROPERTY VALUE SOURCE datab/users mountpoint /datab/users default datab/users compression off default
For more information.

the device is placed online. build 120: In this release.
■
■
■
For more information. device replacement must be initiated by the administrator by using the zpool replace command. If a hot spare was activated when the device was reinserted. any new device that is found in the same physical location as a device that previously belonged to the pool is automatically formatted and replaced. If set to off.5G 18K /users/home/markm users/home/markm@today 0 18K users/home/marks 18K 16.
■
The storage pool state REMOVED is provided when a device or hot spare has been physically removed while the system was running. you might have to use the cfgadm -c configure command to configure a SATA drive.What's New in ZFS?
ZFS Hot-Plugging Enhancements
Oracle Solaris 11 Express. see zpool(1M). Automatic detection when devices are removed or inserted is hardware-dependent and might not be supported on all platforms. build 120: You can recursively rename all descendent ZFS snapshots by using the zfs rename -r command.5G 20K /users users/home 76K 16. USB devices are automatically configured upon insertion. The autoreplace property controls automatic device replacement.5G 18K /users/home/neil users/home/neil@today 0 18K Chapter 1 • Oracle Solaris ZFS File System (Introduction) 41
. The default behavior is off. However. For example.
Recursively Renaming ZFS Snapshots (zfs rename -r)
Oracle Solaris 11 Express. the hot spare is removed when the online operation completes. For example: First. a snapshot of a set of ZFS file systems is created. A hot spare device is substituted for the removed device. if available. Hot spares are checked periodically to ensure that they are online and available.5G 18K /users/home/marks users/home/marks@today 0 18K users/home/neil 18K 16. If a device is removed and then reinserted. If set to on.
# zfs snapshot -r users/home@today # zfs list NAME USED AVAIL REFER MOUNTPOINT users 216K 16.
■
You can replace an existing device with an equivalent device without having to use the zpool replace command. ZFS more effectively responds to devices that are removed and can now automatically identify devices that are inserted.5G 22K /users/home users/home@today 0 22K users/home/markm 18K 16.

Storing Multiple Copies of ZFS User Data
Oracle Solaris 11 Express. the snapshots are renamed the following day. For more information about snapshots.What's New in ZFS?
Then. where N equals 1 through 9.5G 18K users/home/neil@yesterday 0 18K
MOUNTPOINT /users /users/home /users/home/markm /users/home/marks /users/home/neil -
A snapshot is the only type of dataset that can be renamed recursively. see “Overview of ZFS Snapshots” on page 195 and this blog entry that describes how to create rolling snapshots: http://blogs.sun.5G 22K users/home@yesterday 0 22K users/home/markm 18K 16. if possible. In this Solaris release. For example:
# zfs create -o compression=gzip users/home/snapshots # zfs get compression users/home/snapshots NAME PROPERTY VALUE SOURCE users/home/snapshots compression gzip local # zfs create -o compression=gzip-9 users/home/oldfiles # zfs get compression users/home/oldfiles NAME PROPERTY VALUE SOURCE users/home/oldfiles compression gzip-9 local
For more information about setting ZFS properties. see “Setting ZFS Properties” on page 169. For example:
42 Oracle Solaris ZFS Administration Guide • January 2011
. You can specify compression as gzip. you can set gzip compression on ZFS file systems.5G 18K users/home/markm@yesterday 0 18K users/home/marks 18K 16. or gzip-N. ZFS file system metadata is automatically stored multiple times across different disks.com/mmusante/entry/rolling_snapshots_made_easy
gzip Compression Is Available for ZFS
Oracle Solaris 11 Express. build 120: In this Solaris release. This feature is known as ditto blocks. you can also store multiple copies of user data is also stored per file system by using the zfs set copies command. build 120: As a reliability feature.5G 18K users/home/marks@yesterday 0 18K users/home/neil 18K 16. in addition to lzjb compression.5G 20K users/home 76K 16.
# zfs rename -r users/home@today @yesterday # zfs list NAME USED AVAIL REFER users 216K 16.

see this blog: http://blogs. The benefits of storing multiple copies of ZFS user data are as follows:
■
Improves data retention by enabling recovery from unrecoverable block read faults. build 120: You can use the zpool status -v command to display a list of files with persistent errors.
You might consider using ditto blocks when you accidentally create a non-redundant pool and when you need to set data retention policies. see “Repairing a Corrupted File or Directory” on page 285. For more information about displaying a list of files with persistent errors. Enables you to select data protection policies on a per-file system basis. Provides data protection. A subsequent full disk failure might cause all ditto blocks to be unavailable. For a detailed description of how storing multiple copies on a system with a single-disk pool or a multiple-disk pool might impact overall data protection. multiple copies might be placed on a single disk. These copies are in addition to any pool-level redundancy. This method is a convenient way to quickly set up a Solaris iSCSI target. even when only a single disk is available.
■ ■
Note – Depending on the allocation of the ditto blocks in the storage pool. or 3. such as in a mirrored or RAID-Z configuration. such as media faults (commonly known as bit rot) for all ZFS configurations. beyond the capabilities of the storage pool. see “Setting ZFS Properties” on page 169. you had to use the find -inum command to identify the file names from the list of displayed inodes. The default value is 1. For example:
Chapter 1 • Oracle Solaris ZFS File System (Introduction) 43
.What's New in ZFS?
# zfs set copies=2 users/home # zfs get copies users/home NAME PROPERTY VALUE users/home copies 2
SOURCE local
Available values are 1. 2.com/relling/entry/zfs_copies_and_data_protection For more information about setting ZFS properties.sun.
Improved zpool status Output
Oracle Solaris 11 Express.
ZFS and Solaris iSCSI Improvements
Oracle Solaris 11 Express. Previously. you can create a ZFS volume as a Solaris iSCSI target device by setting the shareiscsi property on the ZFS volume. build 120: In this Solaris release.

see “Using a ZFS Volume as a Solaris iSCSI LUN” on page 254. you can set up the iSCSI initiator. the process of sharing file systems has been improved. ZFS shares are automatically designated in the zfs share group.1986-03.What's New in ZFS?
# zfs create -V 2g tank/volumes/v2 # zfs set shareiscsi=on tank/volumes/v2 # iscsitadm list target Target: tank/volumes/v2 iSCSI Name: iqn.sun:02:984fe301-c412-ccc1-cc80-cf9a72aa062a Connections: 0
After the iSCSI target is created.
Sharing ZFS File System Enhancements
Oracle Solaris 11 Express. Although modifying system configuration files. you can use the sharemgr command to manage ZFS shares.
# sharemgr set -P nfs -p nosuid=true zfs/tank/data # sharemgr show -vp zfs zfs nfs=() zfs/tank/data nfs=(nosuid="true") /tank/data /tank/data/1 /tank/data/2 /tank/data/3
44 Oracle Solaris ZFS Administration Guide • January 2011
.” in System Administration Guide: Devices and File Systems. such as /etc/dfs/dfstab. build 120: In this Solaris release. You must preface ZFS share paths with a /zfs designation. The sharemgr command enables you to set and manage share properties on share groups. you can set the ZFS sharenfs property on a ZFS file system to share a ZFS file system. is unnecessary for sharing ZFS file systems. For information about setting up a Solaris iSCSI initiator. For example:
# sharemgr add-share -s tank/data zfs # sharemgr show -vp zfs zfs nfs=() zfs/tank/data /tank/data /tank/data/1 /tank/data/2 /tank/data/3
Then. For example:
# zfs set sharenfs=on tank/home
Or. For more information about managing a ZFS volume as an iSCSI target. you can use the new sharemgr add-share subcommand to share a ZFS file system in the zfs share group. The following example shows how to use sharemgr to set the nosuid property on the shared ZFS file systems. see Chapter 14. “Configuring iSCSI Storage Devices With COMSTAR.com. you can use the sharemgr command to manage ZFS share properties. As in previous releases.

build 120: In this Solaris release. see “ZFS User Properties” on page 165. ZFS provides user properties. build 120: In addition to the standard native properties that can be used to either export internal statistics or control ZFS file system behavior. see “The canmount Property” on page 162. but you can use them to annotate datasets with information that is meaningful in your environment. build 120: In this Solaris release. build 120: The new canmount property enables you to specify whether a dataset can be mounted by using the zfs mount command. you can use various forms of the zfs get command to display information about all datasets if you do not specify a dataset or if you specify all.
ZFS User Properties
Oracle Solaris 11 Express. In previous releases. not just after the file system is created. For more information.
Setting Properties When Creating ZFS File Systems
Oracle Solaris 11 Express. all dataset information was not retreivable with the zfs get command.What's New in ZFS?
ZFS canmount Property
Oracle Solaris 11 Express. For more information. The following examples illustrate equivalent syntax:
# # # # zfs zfs zfs zfs create tank/home set mountpoint=/export/zfs tank/home set sharenfs=on tank/home set compression=on tank/home
# zfs create -o mountpoint=/export/zfs -o sharenfs=on -o compression=on tank/home
Displaying All ZFS File System Information
Oracle Solaris 11 Express. User properties have no effect on ZFS behavior. you can set properties when you create a file system. For example:
# zfs get -s local all tank/home atime tank/home/bonwick atime tank/home/marks quota
off off 50G
local local local
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Oracle Solaris ZFS Administration Guide • January 2011
.

you can use the -r option to recursively create snapshots for all descendent file systems.
Chapter 1 • Oracle Solaris ZFS File System (Introduction) 47
. build 120: A redundant RAID-Z configuration can now have either a single. The snapshots are created together (all at once) or not created at all. Or. Using this option might be necessary when the file system is modified after a rollback occurs but before the receive is initiated. see “Receiving a ZFS Snapshot” on page 209. you can manually replace a device in a storage pool with a hot spare. you can use the -r option to recursively destroy all descendent snapshots when a snapshot is destroyed. For more information. Or.What's New in ZFS?
New zfs receive -F Option
Oracle Solaris 11 Express. The benefit of such an operation is that the snapshot data is always taken at one consistent time. can be sustained.
Recursive ZFS Snapshots
Oracle Solaris 11 Express.or double-parity configuration. see “Creating a RAID-Z Storage Pool” on page 75 or zpool(1M). build 120: In this Solaris release. you can use the new -F option to the zfs receive command to force a rollback of the file system to the most recent snapshot before the receive is initiated.
Double-Parity RAID-Z (raidz2)
Oracle Solaris 11 Express. the hot spare automatically replaces the failed device. You can specify the raidz2 keyword for a double-parity RAID-Z configuration. see “Designating Hot Spares in Your Storage Pool” on page 96 and zpool(1M). even across descendent file systems. In addition.
Hot Spares for ZFS Storage Pool Devices
Oracle Solaris 11 Express. build 120: The ZFS hot spares feature enables you to identify disks that could be used to replace a failed or faulted device in one or more storage pools. which means that one or two device failures. Recursive ZFS snapshots are created quickly as one atomic operation. build 120: When you use the zfs snapshot command to create a file system snapshot. Designating a device as a hot spare means that if an active device in the pool fails. For more information. For more information. without any data loss. see “Creating and Destroying ZFS Snapshots” on page 196. respectively. For more information. you can specify the raidz or raidz1 keyword for a single-parity RAID-Z configuration.

A software inventory is performed so that a snapshot used at a future time can be validated by the system. The snapshot is named SUNWzoneX. For more information. and the uninstall process can detect when a ZFS file system in a zone can be destroyed. see “Upgrading ZFS Storage Pools” on page 123 and zpool(1M). These steps are then performed automatically by the zoneadm command.
Upgrading ZFS Storage Pools (zpool upgrade)
Oracle Solaris 11 Express. This feature is helpful when you want to run tests on an alternative version of a file system and then make that alternative version the active file system. To clone a source zone multiple times. The destination zone's zonepath is used to name the ZFS clone. where X is a unique ID used to distinguish between multiple snapshots. build 120: When the source zonepath and the target zonepath both reside on ZFS and are in the same pool. Note that you can still specify that the ZFS zonepath be copied instead of the ZFS clone. the zpool status command has been modified to notify you when your pools are running older versions of ZFS. build 120: You can upgrade your storage pools to a newer version of ZFS to take advantage of the latest features by using the zpool upgrade command. see “Replacing a ZFS File System With a ZFS Clone” on page 206 and zfs(1M). Keep the following points in mind when using ZFS on a system with Solaris containers installed:
■
Do not use the ZFS snapshot features to clone a zone
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Oracle Solaris ZFS Administration Guide • January 2011
. the zone install process now has the capability to detect when a ZFS file system can be created for a zone. The system validates that the existing snapshot is usable on the target. In addition.
Using ZFS to Clone Non-Global Zones and Other Enhancements
Oracle Solaris 11 Express.What's New in ZFS?
Replacing a ZFS File System With a ZFS Clone (zfs promote)
Oracle Solaris 11 Express. if desired. Additionally. This enhancement means that zoneadm clone will take a ZFS snapshot of the source zonepath and set up the target zonepath. For more information. build 120: The zfs promote command enables you to replace an existing ZFS file system with a clone of that file system. zoneadm clone now automatically uses the ZFS clone feature to clone a zone. a new parameter added to zoneadm allows you to specify that an existing snapshot should be used.

see “Recovering Destroyed ZFS Storage Pools” on page 121. and pool errors associated with pool or device failures are also reported. HOSTNAME: neo SOURCE: zfs-diagnosis. SEVERITY: Major EVENT-TIME: Wed Jun 30 14:53:39 MDT 2010 PLATFORM: SUNW. VER: 1. REV: 1. AUTO-RESPONSE: No automated response will occur. For more information. Oracle Solaris 10 Containers. REC-ACTION: Run ’zpool status -x’ and replace the bad device. you might see a message similar to the following:
SUNW-MSG-ID: ZFS-8000-D3. build 120: This release includes a ZFS diagnostic engine that is capable of diagnosing and reporting pool failures and device failures.0 EVENT-ID: 504a1188-b270-4ab0-af4e-8a77680576b8 DESC: A ZFS device failed.
ZFS Backup and Restore Commands Are Renamed
Oracle Solaris 11 Express. Refer to http://sun. For more information. build 120: This release includes the zpool import -D command. TYPE: Fault. nor does it include proactive actions based on fault analysis. device. see System Administration Guide: Oracle Solaris Zones. the zfs backup and zfs restore commands are renamed to zfs send and zfs receive to more accurately describe their functions. I/O.com/msg/ZFS-8000-D3 for more information. see “Sending and Receiving ZFS Data” on page 207. Checksum. build 120: In this Solaris release. For more information about these commands. and Resource Management. These commands send and receive ZFS data stream representations. CSN: -. The diagnostic engine does not include predictive analysis of checksum and I/O errors.
ZFS Is Integrated With Fault Manager
Oracle Solaris 11 Express.
For more information.
Recovering Destroyed Storage Pools
Oracle Solaris 11 Express. which enables you to recover pools that were previously destroyed with the zpool destroy command.Sun-Fire-880. see “Adding ZFS File Systems to a Non-Global Zone” on page 257 or “Delegating Datasets to a Non-Global Zone” on page 257.
Chapter 1 • Oracle Solaris ZFS File System (Introduction) 49
.What's New in ZFS?
■
You can delegate or add a ZFS file system to a non-global zone. IMPACT: Fault tolerance of the pool may be compromised. If a ZFS failure occurs.

you can quickly identify and resolve the failure.82M 5.76M 1. fsstat. and ls(1). error counts were cleared when a device in a pool was brought online with the zpool online command.
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Oracle Solaris ZFS Administration Guide • January 2011
. You can use the ls -v command to display the verbose ACL format.32M 5.02G 3. build 120: A new file system monitoring tool.
The zpool clear Command
Oracle Solaris 11 Express. you can set and display NFSv4 ACLs in two formats: verbose and compact. see “Clearing Storage Pool Device Errors” on page 94 and zpool(1M). reports file system operations. For an example of recovering from a reported ZFS problem. build 120: This release includes the zpool clear command for clearing error counts associated with a device or a pool. You can use the chmod command to set either ACL formats. Previously. see “Resolving a Missing Device” on page 272.What's New in ZFS?
By reviewing the recommended action. For more information.60G 87. see fsstat(1M). build 120: In this release. The following example shows general ZFS file system activity:
$ fsstat zfs new name name attr attr lookup rddir read read write write file remov chng get set ops ops ops bytes ops bytes 7. see “Setting and Displaying ACLs on ZFS Files in Compact Format” on page 234.
Compact NFSv4 ACL Format
Oracle Solaris 11 Express. chmod(1).92M 2.0M 363M 1. You can use the ls -V command to display the compact ACL format. Activity can be reported by mount point or by file system type.
File System Monitoring Tool (fsstat)
Oracle Solaris 11 Express. For more information. which is to follow the more specific directions in the zpool status command.86T 20.9M 251G zfs
For more information.

Historically. ZFS aggregates devices into a storage pool. between the time a data block is allocated and when it is linked into a directory. This design added another layer of complexity and ultimately prevented certain file system advances because the file system had no control over the physical placement of data on the virtualized volumes. and easy to administer. This problem of inconsistent file systems caused great pain to administrators. and so on) and acts as an arbitrary data store from which file systems can be created. ZFS eliminates volume management altogether. Traditional file systems overwrite data in place. the concept of a volume manager was introduced to provide a representation of a single device so that file systems would not need to be modified to take advantage of multiple devices. More recently. the operating system doesn't force you to run commands to configure the memory and assign it to individual processes.
Transactional Semantics
ZFS is a transactional file system. This command was responsible for reviewing and verifying the file system state. You no longer need to predetermine the size of a file system. the file system will be left in an inconsistent state. The storage pool describes the physical characteristics of the storage (device layout. File systems are no longer constrained to individual devices. This process introduces unnecessary overhead because the data needs to be written twice. as file systems grow automatically within the disk space allocated to the storage pool. which means that the file system state is always consistent on disk. all file systems within the pool can immediately use the additional disk space without additional work. allowing them to share disk space with all file systems in the pool. When new storage is added. Historically. In many ways. with features and benefits not found in any other file system available today. Instead of forcing you to create virtualized volumes. this problem was solved through the use of the fsck command. All processes on the system automatically use the additional memory. which means that if the system loses power.
ZFS Pooled Storage
ZFS uses the concept of storage pools to manage physical storage. such as when the journal cannot be replayed properly. often resulting in a new set of problems.
Chapter 1 • Oracle Solaris ZFS File System (Introduction) 51
. ZFS is robust. data redundancy. for example. which can then be replayed safely if a system crash occurs. and attempting to repair any inconsistencies during the process. scalable. To address multiple devices and provide for data redundancy. file systems were constructed on top of a single physical device.What Is ZFS?
What Is ZFS?
The Solaris ZFS file system is a revolutionary new file system that fundamentally changes the way file systems are administered. The journaling process records actions in a separate journal. the storage pool works similarly to a virtual memory system: When a memory DIMM is added to a system. file systems have introduced the concept of journaling. and the fsck command was never guaranteed to fix all possible problems.

and any sequence of operations is either entirely committed or entirely ignored. Directories can have up to 248 (256 trillion) entries. When a bad data block is detected. In addition. Initially. allowing for 256 quadrillion zettabytes of storage. ZFS fetches the correct data from another redundant copy and repairs the bad data.
52 Oracle Solaris ZFS Administration Guide • January 2011
. As a result. snapshots consume no additional disk space within the pool. the file system itself will always be consistent. out of necessity due to the volume management layer and traditional file system design. synchronous data (written using the O_DSYNC flag) is always guaranteed to be written before returning. Traditional file systems that do provide checksum verification have performed it on a per-block basis. Although the most recently written pieces of data might be lost. the file system can never be corrupted through accidental loss of power or a system crash. Snapshots can be created quickly and easily.
ZFS Snapshots
A snapshot is a read-only copy of a file system or volume. the snapshot prevents the data from being freed back to the pool. can result in data that is incorrect but has no checksum errors. All checksum verification and data recovery are performed at the file system layer. data is managed using copy on write semantics. and no limit exists on the number of file systems or the number of files that can be contained within a file system. replacing it with the correct data.What Is ZFS?
With a transactional file system. so no need exists to preallocate inodes or otherwise limit the scalability of the file system when it is first created.
Checksums and Self-Healing Data
With ZFS. Data is never overwritten. ZFS supports storage pools with varying levels of data redundancy. All the algorithms have been written with scalability in mind. As data within the active dataset changes. the snapshot consumes disk space by continuing to reference the old data. Thus. and are transparent to applications. All metadata is allocated dynamically.
Unparalleled Scalability
A key design element of the ZFS file system is scalability. In addition. all data and metadata is verified using a user-selectable checksum algorithm. ZFS provides for self-healing data. so it is never lost. such as writing a complete block to an incorrect location. The traditional design means that certain failures. The file system itself is 128 bit. ZFS checksums are stored in a way such that these failures are detected and can be recovered from gracefully.

ZFS manages file systems through a hierarchy that allows for this simplified management of properties such as quotas. The alternate boot environment can become the primary boot environment by running the luactivate command. and so on. Through the use of a hierarchical file system layout. ZFS provides a greatly simplified administration model. For information about clones. The checksum capability can range from the simple and fast fletcher4 (the default) to cryptographically strong hashes such as SHA256. This design enables you to define fine-grained management points. Datasets are identified using the following format: pool/path[@snapshot] pool Identifies the name of the storage pool that contains the dataset
53
checksum
clone
Chapter 1 • Oracle Solaris ZFS File System (Introduction)
. compression. file systems are the central point of control. see “Overview of ZFS Clones” on page 205. turn compression on or off. File systems themselves are very cheap (equivalent to creating a new directory). A 256-bit hash of the data in a file system block.
ZFS Terminology
This section describes the basic terminology used throughout this book: alternate boot environment A boot environment that is created by the lucreate command and possibly updated by the luupgrade command. ZFS makes it easy to create and manage file systems without requiring multiple commands or the editing configuration files. so you are encouraged to create a file system for each user. A file system whose initial contents are identical to the contents of a snapshot. You can easily set quotas or reservations. dataset A generic name for the following ZFS components: clones. and automatic management of mount points and NFS share semantics. file systems. and volumes. You can examine or replace devices without learning a separate set of volume manager commands. In this model. property inheritance.ZFS Terminology
Simplified Administration
Most importantly. You can send and receive file system snapshot streams. reservations. Each dataset is identified by a unique name in the ZFS namespace. workspace. snapshots. or manage mount points for numerous file systems with a single command. and mount points. project. but it is not the active or primary boot environment.

“Managing Oracle Solaris ZFS File Systems. see Chapter 4. This default can be overridden by using the lucreate -s option.ZFS Terminology
path snapshot
Is a slash-delimited path name for the dataset component Is an optional component that identifies a snapshot of a dataset
For more information about datasets. This process is referred to as mirror resynchronization in traditional volume management products. For more information about file systems. A virtual device that stores data and parity on multiple disks. “Managing Oracle Solaris ZFS Storage Pools. A logical group of devices describing the layout and physical characteristics of the available storage. For example. the primary boot environment is the current boot environment. For more information about ZFS resilvering. see Chapter 6. see “RAID-Z Storage Pool Configuration” on page 71. The process of copying data from one device to another device is known as resilvering.” file system A ZFS dataset of type filesystem that is mounted within the standard system namespace and behaves like other file systems. the data from an up-to-date mirror device is copied to the newly restored mirror device. “Managing Oracle Solaris ZFS File Systems. snapshot A read-only copy of a file system or volume at a given point in time. If any disk in a mirror fails. By default. see “Viewing Resilvering Status” on page 281. Disk space for datasets is allocated from a pool. For more information about storage pools.” primary boot environment A boot environment that is used by the lucreate command to build the alternate boot environment. if a mirror device is replaced or taken offline. any other disk in that mirror can provide the same data.
pool
RAID-Z
resilvering
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Oracle Solaris ZFS Administration Guide • January 2011
. see Chapter 6.” mirror A virtual device that stores identical copies of data on two or more disks. For more information about RAID-Z.

you can create a ZFS volume as a swap device. volume A dataset that represents a block device. Pool names must not contain a percent sign (%).ZFS Component Naming Requirements
For more information about snapshots. empty components are not allowed. a file. see “Displaying Storage Pool Virtual Device Information” on page 78.
Chapter 1 • Oracle Solaris ZFS File System (Introduction)
55
. or spare is not allowed because these names are reserved. see “ZFS Volumes” on page 253. must be named according to the following rules:
■
Each component can only contain alphanumeric characters in addition to the following four special characters:
■ ■ ■ ■
Underscore (_) Hyphen (-) Colon (:) Period (. raidz. Dataset names must not contain a percent sign (%). or a collection of devices. The name log is reserved. virtual device A logical device in a pool. A name that begins with mirror.
In addition. raidz1.) The beginning sequence c[0-9] is not allowed. raidz2. such as datasets and pools. raidz3. For more information about ZFS volumes. except for the following restrictions:
■ ■ ■
■ ■ ■
Dataset names must begin with an alphanumeric character. which can be a physical device. see “Overview of ZFS Snapshots” on page 195.
ZFS Component Naming Requirements
Each ZFS component. For example.
■
Pool names must begin with a letter. For more information about virtual devices.

56
.

you will have a basic understanding of how the ZFS commands work. The following sections are provided in this chapter:
■ ■ ■ ■
“ZFS Hardware and Software Requirements and Recommendations” on page 57 “Creating a Basic ZFS File System” on page 58 “Creating a ZFS Storage Pool” on page 59 “Creating a ZFS File System Hierarchy” on page 60
ZFS Hardware and Software Requirements and Recommendations
Ensure that you review the following hardware and software requirements and recommendations before attempting to use the ZFS software:
■
Use a SPARC or x86 based system that is running at least the Oracle Solaris 11 Express release. By the end of this chapter. This chapter does not provide a comprehensive overview and refers to later chapters for more detailed information. The minimum amount of disk space required for a storage pool is 64 MB.C H A P T E R
Getting Started With Oracle Solaris ZFS
2
2
This chapter provides step-by-step instructions on setting up a basic Oracle Solaris ZFS configuration. use multiple controllers. and should be able to create a basic pool and file systems. The minimum amount of memory needed to install a Solaris system is 768 MB. If you create a mirrored disk configuration. The minimum disk size is 128 MB. use at least one GB or more of memory.
■
■
■
57
. However. for good ZFS performance.

and is automatically mounted at /tank. File systems provide points of administration that enable you to manage different sets of data within the same pool.
# zpool create tank mirror c1t0d0 c2t0d0
For more information about redundant ZFS pool configurations. and is automatically mounted at /tank/fs. tank. you probably want to create additional file systems. tank/fs. can use available disk space as needed. can use available disk space as needed. a new ZFS file system is created and mounted automatically. when you create a new pool. Assume that the whole disks /dev/dsk/c1t0d0 and /dev/dsk/c2t0d0 are available for use. The following example shows how to create a file system named fs in the storage pool tank.Creating a Basic ZFS File System
Creating a Basic ZFS File System
ZFS administration has been designed with simplicity in mind. see “Replication Features of a ZFS Storage Pool” on page 70. For example. The following example shows how to create a basic mirrored storage pool named tank and a ZFS file system named tank in one command. For information about creating a hierarchy of ZFS file systems. see “Creating a ZFS File System Hierarchy” on page 60.
# mkfile 100m /tank/foo # df -h /tank Filesystem size used avail capacity Mounted on tank 80G 100M 80G 1% /tank
Within a pool. The new ZFS file system.
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Oracle Solaris ZFS Administration Guide • January 2011
.
# zfs create tank/fs
The new ZFS file system. you want to create and organize a hierarchy of file systems that matches your organizational needs. Among the design goals is to reduce the number of commands needed to create a usable file system.
# mkfile 100m /tank/fs/foo # df -h /tank/fs Filesystem size tank/fs 80G
used avail capacity Mounted on 100M 80G 1% /tank/fs
Typically.

ZFS supports nonredundant (striped) configurations. In the storage example in “How to Create a ZFS Storage Pool” on page 59. assume that the whole disks /dev/dsk/c1t0d0 and /dev/dsk/c2t0d0 are available for use.
1
2
Choose data replication. you must determine which devices will store your data. and they must not be in use by other parts of the operating system. which determines the types of hardware failures the pool can withstand. For more information about disks and how they are used and labeled. or they can be entire disks that ZFS formats as a single large slice. The remainder of this chapter provides a more complete example. The devices can be individual slices on a preformatted disk. For more information about ZFS replication features. These devices must be disks of at least 128 MB in size. see “ZFS Rights Profiles” on page 262. For more information about the ZFS rights profiles. In the storage example in “How to Create a ZFS Storage Pool” on page 59. similar to what you would encounter in your environment.Creating a ZFS Storage Pool
Creating a ZFS Storage Pool
The previous example illustrates the simplicity of ZFS.
▼
How to Identify Storage Requirements for Your ZFS Storage Pool
Determine available devices for your storage pool. The pool describes the physical characteristics of the storage and must be created before any file systems are created.
Chapter 2 • Getting Started With Oracle Solaris ZFS
59
. as well as mirroring and RAID-Z (a variation on RAID-5). ZFS supports multiple types of data replication. basic mirroring of two available disks is used.
▼
1
How to Create a ZFS Storage Pool
Become root or assume an equivalent role with the appropriate ZFS rights profile. Before creating a storage pool. see “Using Disks in a ZFS Storage Pool” on page 67. The first tasks are to identify your storage requirements and create a storage pool. see “Replication Features of a ZFS Storage Pool” on page 70.

You can determine if your pool was successfully created by using the zpool list command. This name is used to identify the storage pool when you are using the zpool and zfs commands. They are lightweight and can be created easily. Create the pool.
4
View the results. ZFS file systems are the central point of administration. see “Detecting In-Use Devices” on page 79. see “Creating a ZFS Storage Pool” on page 73. as this model allows properties.
Oracle Solaris ZFS Administration Guide • January 2011
60
. snapshots. ZFS leverages this hierarchy by supporting property inheritance so that common properties can be set quickly and easily on entire trees of file systems. For more information about how device usage is determined.Creating a ZFS File System Hierarchy
2
Pick a name for your storage pool. see “Querying ZFS Storage Pool Status” on page 105. Hierarchies are simple yet powerful mechanisms for organizing information. you can create your file system hierarchy. the command cannot create the pool.
Creating a ZFS File System Hierarchy
After creating a storage pool to store your data. The root of the hierarchy is always the pool name. A good model to use is to establish one file system per user or project. For more information about creating storage pools. ZFS allows file systems to be organized into hierarchies. but it must satisfy the naming requirements in “ZFS Component Naming Requirements” on page 55. They are also very familiar to anyone who has used a file system. the following command creates a mirrored pool that is named tank:
# zpool create tank mirror c1t0d0 c2t0d0
3
If one or more devices contains another file system or is otherwise in use.
▼
1
How to Determine Your ZFS File System Hierarchy
Pick the file system granularity. and backups to be controlled on a per-user or per-project basis. Most systems require only a single pool.
# zpool list NAME tank SIZE 80G ALLOC 137K FREE 80G CAP HEALTH 0% ONLINE ALTROOT -
For more information about viewing pool status. where each file system has only a single parent. For example. so you can pick any name that you prefer.

For example:
# zfs create -o mountpoint=/export/zfs -o sharenfs=on -o compression=on tank/home
Chapter 2 • Getting Started With Oracle Solaris ZFS 61
. set up any properties to be shared among all users:
# zfs set # zfs set # zfs set # zfs get NAME tank/home mountpoint=/export/zfs tank/home sharenfs=on tank/home compression=on tank/home compression tank/home PROPERTY VALUE compression on
SOURCE local
You can set file system properties when the file system is created. For more information about managing file systems. are created in “How to Create ZFS File Systems” on page 61. Create the desired hierarchy. For more information about the ZFS rights profiles. After the file system hierarchy is established. a quota of 10 GB on user bonwick is enforced. This model provides a central point of administration for controlling properties and administering file systems. These properties control a variety of behaviors. For more information about properties.”
2
Group similar file systems. are shared by using NFS.
3
Choose the file system properties. and if any quotas are in effect. “Managing Oracle Solaris ZFS File Systems. Similar file systems should be created under a common name. ZFS allows file systems to be organized into hierarchies so that similar file systems can be grouped.
# zfs create tank/home
2
3
Set the inherited properties.Creating a ZFS File System Hierarchy
Two ZFS file systems. if they use compression. all home directories are mounted at /export/zfs/user.
▼
1
How to Create ZFS File Systems
Become root or assume an equivalent role with the appropriate ZFS rights profile. see Chapter 6. In this example. the two file systems are placed under a file system named home. In the example in “How to Create ZFS File Systems” on page 61. including where the file systems are mounted. Most file system characteristics are controlled by properties. how they are shared. see “Introducing ZFS Properties” on page 149. In the example in “How to Create ZFS File Systems” on page 61. see “ZFS Rights Profiles” on page 262. In addition. a file system that acts as a container for individual file systems is created. and have compression enabled. bonwick and billm.

You do not need to edit the /etc/vfstab or /etc/dfs/dfstab file. while user billm can use the full pool (67 GB). see “Creating a ZFS File System” on page 146. so they are automatically mounted at /export/zfs/user and are NFS shared.5K /tank 67. Next. For more information about how disk space is used and calculated.
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Oracle Solaris ZFS Administration Guide • January 2011
. see “Mounting and Sharing ZFS File Systems” on page 173.
5
Set the file system-specific properties. regardless of how much space is available in the pool.0K 8K 8K AVAIL REFER MOUNTPOINT 67.
4
Create the individual file systems. For more information about creating file systems. individual file systems are grouped under the home file system in the pool tank.0G 8K /export/zfs/billm 10.0G 8K /export/zfs/bonwick
Note that user bonwick only has 10 GB of space available. For more information about mounting and sharing file systems. see “Introducing ZFS Properties” on page 149. user bonwick is assigned a quota of 10 GBs. View available file system information by using the zfs list command:
# zfs list NAME tank tank/home tank/home/billm tank/home/bonwick USED 92.0G 8K /export/zfs 67.
# zfs set quota=10G tank/home/bonwick
6
View the results. see “ZFS Disk Space Accounting” on page 64.Creating a ZFS File System Hierarchy
For more information about properties and property inheritance.0K 24. This property places a limit on the amount of space he can consume. File systems could have been created and then the properties could have been changed at the home level. For more information about viewing file system status. see “Querying ZFS File System Information” on page 166. All properties can be changed dynamically while file systems are in use.
# zfs create tank/home/bonwick # zfs create tank/home/billm
These file systems inherit their property values from their parent.0G 9. In this example.

Traditional volume management products help manage this process. You can easily set up and manage many file systems by applying properties that can be inherited by the descendent file systems contained within the hierarchy. see “Creating a ZFS File System Hierarchy” on page 60. The following sections are provided in this chapter:
■ ■ ■ ■ ■ ■
“ZFS File System Granularity” on page 63 “ZFS Disk Space Accounting” on page 64 “Out of Space Behavior” on page 64 “Mounting ZFS File Systems” on page 65 “Traditional Volume Management” on page 65 “New Solaris ACL Model” on page 65
ZFS File System Granularity
Historically. Understanding these key differences can help reduce confusion when you use traditional tools to interact with ZFS. Creating and re-creating traditional file systems because of size constraints are time-consuming and sometimes difficult.C H A P T E R
Oracle Solaris ZFS and Traditional File System Differences
3
3
This chapter discusses some significant differences between Oracle Solaris ZFS and traditional file systems. ZFS file systems grow automatically within the disk space allocated to the storage pool in which they reside.
63
. to manage many user subdirectories. such as /export/home. Instead of creating one file system. file systems have been constrained to one device and thus to the size of that device. For an example that shows how to create a file system hierarchy. similar to the way directories are created. they can be created easily and quickly. you can create one file system per user. Because ZFS file systems are not constrained to specific devices.

Snapshots are common in most ZFS environments. they are called pending changes. The amount of disk space used. then no disk space is gained from the file deletion. This behavior also means that the total number of files supported by the file systems is predetermined. no initial space cost is required. see “Setting Reservations on ZFS File Systems” on page 185. A specified amount of disk space can be guaranteed to a file system by using reservations. Most other file systems preallocate much of their metadata. Even committing a change to disk by using fsync(3c) or O_SYNC does not necessarily guarantee that the disk space usage information is updated immediately. The blocks used by the file continue to be referenced from the snapshot. and the number of files is limited only by the available disk space. see: http://hub. at file system creation time. This model is very similar to the NFS model. given appropriate permissions. ZFS is a transactional file system.
64 Oracle Solaris ZFS Administration Guide • January 2011
. Because ZFS allocates its metadata as it needs it. you can remove a file from a full file system. For information about quotas. The output from the df -g command must be interpreted differently for ZFS than other file systems. the available disk space reported by utilities such as df might change even when the file system is inactive.opensolaris. So.ZFS Disk Space Accounting
ZFS Disk Space Accounting
ZFS is based on the concept of pooled storage. However. if the file to be removed exists in a snapshot of the file system. all ZFS file systems in a pool share the available storage in the pool. where multiple directories are mounted from the same file system (consider /home). an immediate space cost for this metadata is required. All metadata in ZFS is allocated dynamically. For additional details about ZFS disk space consumption as reported by the du and df commands.” The presence of snapshots can cause some unexpected behavior when you attempt to free disk space.org/bin/view/Community+Group+zfs/faq/#whydusize
Out of Space Behavior
File system snapshots are inexpensive and easy to create in ZFS. available. which are mapped to physical storage. Most file system modifications are bundled into transaction groups and committed to disk asynchronously. Note that the maximum file system size can be limited by using quotas. For information about ZFS snapshots. For information about reservations. see “Setting Quotas on ZFS File Systems” on page 182. and this action results in more disk space becoming available in the file system. “Working With Oracle Solaris ZFS Snapshots and Clones. Pending changes are generally accounted for within a few seconds. Until these modifications are committed to disk. Typically. The total files reported is only an estimate based on the amount of storage that is available in the pool. As a result. and referenced by a file or file system does not consider pending changes. Unlike typical file systems. as other file systems in the pool consume or release disk space. see Chapter 7.

you must edit the /etc/vfstab file every time you add a new file system. Using logical volumes might sacrifice performance. as ZFS works best when it uses raw physical devices.
■
For more information about using ACLs with ZFS files. reliability. This model provides a much more granular set of access privileges. so it is possible to create a storage pool comprised of logical volumes.
New Solaris ACL Model
Previous versions of the Solaris OS supported an ACL implementation that was primarily based on the POSIX ACL draft specification. The main differences of the new Solaris ACL model are as follows:
■ ■ ■
The model is based on the NFSv4 specification and is similar to NT-style ACLs.New Solaris ACL Model
As a result. and so on. or both. with traditional file systems. You do not need to manage ZFS entries in the /etc/vfstab file. see “Mounting and Sharing ZFS File Systems” on page 173. This behavior means that you can receive an unexpected ENOSPC or EDQUOT error when attempting to remove a file. see Chapter 8.”
Chapter 3 • Oracle Solaris ZFS and Traditional File System Differences 65
. “Using ACLs and Attributes to Protect Oracle Solaris ZFS Files. A new Solaris ACL model that is based on the NFSv4 specification is used to protect ZFS files. either software or hardware. ZFS has eliminated this requirement by automatically mounting and unmounting file systems according to the properties of the dataset.
Mounting ZFS File Systems
ZFS reduces complexity and eases administration. ZFS eliminates the need for a separate volume manager. Richer inheritance semantics designate how access privileges are applied from directory to subdirectories. The POSIX-draft based ACLs are used to protect UFS files. This configuration is not recommended. and should be avoided. the file deletion can consume more disk space because a new version of the directory needs to be created to reflect the new state of the namespace. For more information about mounting and sharing ZFS file systems. For example. ACLs are set and displayed with the chmod and ls commands rather than the setfacl and getfacl commands.
Traditional Volume Management
As described in “ZFS Pooled Storage” on page 51. ZFS operates on raw devices.

66
.

A storage device can be a whole disk (c1t0d0) or an individual slice (c0t0d0s7). The recommended mode of operation is to use an entire disk. in which case the disk does not
67
. Typically. Physical storage can be any block device of at least 128 MB in size.C H A P T E R
Managing Oracle Solaris ZFS Storage Pools
4
4
This chapter describes how to create and administer storage pools in Oracle Solaris ZFS. this device is a hard drive that is visible to the system in the /dev/dsk directory. The following sections are provided in this chapter:
■ ■ ■ ■ ■ ■ ■ ■
“Components of a ZFS Storage Pool” on page 67 “Replication Features of a ZFS Storage Pool” on page 70 “Creating and Destroying ZFS Storage Pools” on page 73 “Managing Devices in ZFS Storage Pools” on page 82 “Managing ZFS Storage Pool Properties” on page 102 “Querying ZFS Storage Pool Status” on page 105 “Migrating ZFS Storage Pools” on page 115 “Upgrading ZFS Storage Pools” on page 123
Components of a ZFS Storage Pool
The following sections provide detailed information about the following storage pool components:
■ ■ ■
“Using Disks in a ZFS Storage Pool” on page 67 “Using Slices in a ZFS Storage Pool” on page 69 “Using Files in a ZFS Storage Pool” on page 70
Using Disks in a ZFS Storage Pool
The most basic element of a storage pool is physical storage.

the following are valid disk names:
■ ■ ■
c1t0d0 /dev/dsk/c1t0d0 /dev/foo/disk
Using whole physical disks is the easiest way to create ZFS storage pools. not an EFI label. such as Solaris Volume Manager (SVM) or Veritas Volume Manager (VxVM). such as /dev/dsk/c1t0d0. from management.
■
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Oracle Solaris ZFS Administration Guide • January 2011
. ZFS formats the disk using an EFI label to contain a single. A disk that is intended for a ZFS root pool must be created with an SMI label. you must manually label the disk and provide a slice to ZFS. You can construct logical devices for ZFS using volumes presented by software-based volume managers. To use these disks. the partition table that is displayed by the format command appears similar to the following:
Current partition table (original): Total disk sectors available: 286722878 + 16384 (reserved sectors) Part Tag 0 usr 1 unassigned 2 unassigned 3 unassigned 4 unassigned 5 unassigned 6 unassigned 8 reserved Flag wm wm wm wm wm wm wm wm First Sector 34 0 0 0 0 0 0 286722912 Size 136. ZFS applies an EFI label when you create a storage pool with whole disks. Certain configurations might provide adequate redundancy and performance.00MB Last Sector 286722911 0 0 0 0 0 0 286739295
To use a whole disk. Although ZFS functions properly on such devices. For more information about EFI labels. and performance perspectives.Components of a ZFS Storage Pool
require special formatting. Disks can be specified by using either the full path. However. For example. such as c1t0d0. or volumes presented by software-based volume managers. you need to understand the relationship between ZFS redundancy features and the redundancy features offered by the array. ZFS configurations become progressively more complex. LUNs in hardware RAID arrays. these configurations are not recommended. or a shorthand name that consists of the device name within the /dev/dsk directory. reliability. the disk must be named by using the /dev/dsk/cNtNdN naming convention. but other configurations might not. large slice. You can relabel a disk with an SMI label by using the format -e command. see “EFI Disk Label” in System Administration Guide: Devices and File Systems. less-than-optimal performance might be the result. when you build pools from disk slices. The following considerations might help you determine how to configure ZFS with other hardware or software storage solutions:
■
If you construct a ZFS configuration on top of LUNs from hardware RAID arrays.72GB 0 0 0 0 0 0 8. When used in this way. Some third-party drivers use a different naming convention or place disks in a location other than the /dev/dsk directory.

14086 0 0 .Components of a ZFS Storage Pool
For additional information about storage pool recommendations.com/wiki/index. . might change the device IDs in your ZFS storage pool. such as a firmware update or other hardware change.
Using Slices in a ZFS Storage Pool
Disks can be labeled with a traditional Solaris VTOC (SMI) label when you create a storage pool with a disk slice. see the ZFS best practices site: http://www. The simplest configuration would be to put the entire disk capacity in slice 0 and use that slice for the root pool. A system event. For a bootable ZFS root pool. Specify disk (enter its number): 4 selecting c1t1d0 partition> p Current partition table (original): Total disk cylinders available: 14087 + 2 (reserved cylinders) Part Tag 0 root 1 unassigned 2 backup 3 unassigned 4 unassigned 5 unassigned 6 unassigned 7 unassigned Flag wm wm wm wm wm wm wm wm Cylinders 0 . On systems where device ID information is available. this identification method allows devices to be reconfigured without updating ZFS.php/ZFS_Best_Practices_Guide Disks are identified both by their path and by their device ID. On a SPARC based system.solarisinternals. the disks in the pool must contain slices and the disks must be labeled with an SMI label. Slice 8 requires no administration and cannot be changed. Because device ID generation and management can vary by system. if available. . A small amount of boot information is contained in slice 8. which can cause the devices to become unavailable.
Chapter 4 • Managing Oracle Solaris ZFS Storage Pools 69
. a 72-GB disk has 68 GB of usable disk space located in slice 0.14086 0 0 0 0 0 Size 68.35GB 0 68.35GB 0 0 0 0 0 Blocks (14087/0/0) 143349312 (0/0/0) 0 (14087/0/0) 143349312 (0/0/0) 0 (0/0/0) 0 (0/0/0) 0 (0/0/0) 0 (0/0/0) 0
On an x86 based system. export the pool first before moving devices. a 72-GB disk has 68 GB of usable space located in slice 0 as shown in the following format output:
# format . such as moving a disk from one controller to another controller. as shown in the following format output.

This feature is aimed primarily at testing and enabling simple experimentation. An fdisk partition is represented by a /dev/dsk/cN[tN]dNpN device name and acts as a container for the disk's available slices.
Using Files in a ZFS Storage Pool
ZFS also allows you to use UFS files as virtual devices in your storage pool. The reason is that any use of files relies on the underlying file system for consistency. as well as self-healing properties. All files must be specified as complete paths and must be at least 64 MB in size. .
■ ■ ■ ■ ■
“Mirrored Storage Pool Configuration” on page 71 “RAID-Z Storage Pool Configuration” on page 71 “Self-Healing Data in a Redundant Configuration” on page 72 “Dynamic Striping in a Storage Pool” on page 72 “ZFS Hybrid Storage Pool” on page 72
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Oracle Solaris ZFS Administration Guide • January 2011
.Replication Features of a ZFS Storage Pool
# format . Do not use a cN[tN]dNpN device for a ZFS storage pool component because this configuration is neither tested nor supported.
Replication Features of a ZFS Storage Pool
ZFS provides data redundancy.41MB 0 Blocks (49778/0/0) 143360640 (0/0/0) 0 (49779/0/0) 143363520 (0/0/0) 0 (0/0/0) 0 (0/0/0) 0 (0/0/0) 0 (0/0/0) 0 (1/0/0) 2880 (0/0/0) 0
An fdisk partition also exists on Solaris x86 systems.49778 0 0 0 0 0 0 0 0 Size 68. .36GB 0 68. files can be quite useful when you are first trying out ZFS or experimenting with more complicated configurations when insufficient physical devices are present. However. selecting c1t0d0 partition> p Current partition table (original): Total disk cylinders available: 49779 + 2 (reserved cylinders) Part Tag 0 root 1 unassigned 2 backup 3 unassigned 4 unassigned 5 unassigned 6 unassigned 7 unassigned 8 boot 9 unassigned Flag wm wu wm wu wu wu wu wu wu wu Cylinders 1 . in mirrored and RAID-Z configurations.49778 0 0 . then you are implicitly relying on UFS to guarantee correctness and synchronous semantics.36GB 0 0 0 0 0 1. If you create a ZFS pool backed by files on a UFS file system. not for production use.

A RAID-Z configuration with N disks of size X with P parity disks can hold approximately (N-P)*X bytes and can withstand P device(s) failing before data integrity is compromised. ZFS uses variable-width RAID stripes so that all writes are full-stripe writes. no special hardware is required to create a RAID-Z configuration. Conceptually. preferably on separate controllers. For example.sun. Conceptually. a RAID-Z configuration with three disks would look similar to the following:
raidz c1t0d0 c2t0d0 c3t0d0
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.com/ahl/entry/triple_parity_raid_z All traditional RAID-5-like algorithms (RAID-4. if you have three disks in a single-parity RAID-Z configuration. a basic mirrored configuration would look similar to the following:
mirror c1t0d0 c2t0d0
Conceptually. For more information about RAIDZ-3 (raidz3). and EVEN-ODD. double-. RAID-6. RAID-Z is the world's first software-only solution to the RAID-5 write hole. and therefore forever useless. see “Creating a Mirrored Storage Pool” on page 74. see the following blog: http://blogs. you can create more than one mirror in each pool. Single-parity RAID-Z (raidz or raidz1) is similar to RAID-5. In RAID-Z. the parity will remain unsynchronized with the data. (unless a subsequent full-stripe write overwrites it). This design is only possible because ZFS integrates file system and device management in such a way that the file system's metadata has enough information about the underlying data redundancy model to handle variable-width RAID stripes. or triple-parity fault tolerance.Replication Features of a ZFS Storage Pool
Mirrored Storage Pool Configuration
A mirrored storage pool configuration requires at least two disks. a more complex mirrored configuration would look similar to the following:
mirror c1t0d0 c2t0d0 c3t0d0 mirror c4t0d0 c5t0d0 c6t0d0
For information about creating a mirrored storage pool. RDP.
RAID-Z Storage Pool Configuration
In addition to a mirrored storage pool configuration. Double-parity RAID-Z (raidz2) is similar to RAID-6. and power is lost before all blocks have been written to disk. for example) might experience a problem known as the “RAID-5 write hole. ZFS provides a RAID-Z configuration with either single-. Otherwise. In addition.” If only part of a RAID-5 stripe is written. parity data occupies disk space equal to one of the three disks. You need at least two disks for a single-parity RAID-Z configuration and at least three disks for a double-parity RAID-Z configuration. Many disks can be used in a mirrored configuration.

you can select the ZFS redundancy configuration of the storage pool and easily manage other configuration options. For more information about choosing between a mirrored configuration or a RAID-Z configuration based on performance and disk space considerations. a more complex RAID-Z configuration would look similar to the following:
raidz c1t0d0 c2t0d0 c3t0d0 c4t0d0 c5t0d0 c6t0d0 c7t0d0 raidz c8t0d0 c9t0d0 c10t0d0 c11t0d0 c12t0d0 c13t0d0 c14t0d0
If you are creating a RAID-Z configuration with many disks. see the following blog entry: http://blogs.php/ZFS_Best_Practices_Guide
ZFS Hybrid Storage Pool
The ZFS hybrid storage pool. to improve performance and increase capacity. not only does ZFS fetch the correct data from another redundant copy. while reducing power consumption. available in Oracle's Sun Storage 7000 product series. but it also repairs the bad data by replacing it with the good copy. SSDs. see “Creating a RAID-Z Storage Pool” on page 75. For example. is a special storage pool that combines DRAM.
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.com/wiki/index. For information about creating a RAID-Z storage pool. With this product's management interface. RAID-Z configurations with single-digit groupings of disks should perform better. see the Sun Storage Unified Storage System Administration Guide.
Self-Healing Data in a Redundant Configuration
ZFS provides self-healing data in a mirrored or RAID-Z configuration.solarisinternals.Replication Features of a ZFS Storage Pool
Conceptually. see the ZFS best practices site: http://www. The decision about where to place data is done at write time. For more information about this product.com/roch/entry/when_to_and_not_to For additional information about RAID-Z storage pool recommendations.
Dynamic Striping in a Storage Pool
ZFS dynamically stripes data across all top-level virtual devices. a RAID-Z configuration with 14 disks is better split into two 7-disk groupings. When a bad data block is detected. consider splitting the disks into multiple groupings. and HDDs. so no fixed-width stripes are created at allocation time.sun.

This simple command has significant consequences.
Creating a ZFS Storage Pool
To create a storage pool. For example. However. Destroying a pool is easier than creating one. Each virtual device can also be a mirror or a RAID-Z device that contains other disk devices or files. you could create the following configurations out of four disks:
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Four disks using dynamic striping One four-way RAID-Z configuration Two two-way mirrors using dynamic striping
Although ZFS supports combining different types of virtual devices within the same pool. ZFS gradually allocates data to the new device in order to maintain performance and disk space allocation policies. The pool name must satisfy the naming requirements in “ZFS Component Naming Requirements” on page 55. Use zpool destroy with caution.Creating and Destroying ZFS Storage Pools
When new virtual devices are added to a pool. avoid this practice. For example. your fault tolerance is as good as your worst virtual device.
Creating a Basic Storage Pool
The following command creates a new pool named tank that consists of the disks c1t0d0 and c1t1d0:
# zpool create tank c1t0d0 c1t1d0
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. you can create a pool with a two-way mirror and a three-way RAID-Z configuration. RAID-Z in this case. ZFS cannot always know when a device is already in use. However. A best practice is to use top-level virtual devices of the same type with the same redundancy level in each device.
Creating and Destroying ZFS Storage Pools
The following sections describe different scenarios for creating and destroying ZFS storage pools:
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“Creating a ZFS Storage Pool” on page 73 “Displaying Storage Pool Virtual Device Information” on page 78 “Handling ZFS Storage Pool Creation Errors” on page 79 “Destroying ZFS Storage Pools” on page 81
Creating and destroying pools is fast and easy. be cautious when performing these operations. This command takes a pool name and any number of virtual devices as arguments. This configuration gives you flexibility in controlling the fault characteristics of your pool. use the zpool create command. Although checks are performed to prevent using devices known to be in use in a new pool.

solarisinternals. see “Attaching and Detaching Devices in a Storage Pool” on page 87. identical pool.com/wiki/index. Detaching a disk in a mirrored configuration as long as the remaining devices provide adequate redundancy for the configuration. The following command creates a pool with two. Replacing a disk or disks in an existing mirrored configuration as long as the replacement disks are greater than or equal to the size of the device to be replaced.php/ZFS_Best_Practices_Guide Currently. For more information. Or.
Creating a Mirrored Storage Pool
To create a mirrored pool. see “Creating a New Pool By Splitting a Mirrored ZFS Storage Pool” on page 89. Data is dynamically striped across both mirrors. see “Replacing Devices in a Storage Pool” on page 94. For more information. two-way mirrors:
# zpool create tank mirror c1d0 c2d0 mirror c3d0 c4d0
The second mirror keyword indicates that a new top-level virtual device is being specified. large slice. see the following site: http://www. see “Adding Devices to a Storage Pool” on page 82. Attaching additional disks to an existing mirrored configuration. use the mirror keyword.
Creating a ZFS Root Pool
You can install and boot from a ZFS root file system. For more information.Creating and Destroying ZFS Storage Pools
Device names representing the whole disks are found in the /dev/dsk directory and are labeled appropriately by ZFS to contain a single. For more information. attaching additional disks to a non-replicated configuration to create a mirrored configuration.
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You cannot outright remove a device that is not a log or a cache device from a mirrored storage pool. the following operations are supported in a ZFS mirrored configuration:
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Adding another set of disks for an additional top-level virtual device (vdev) to an existing mirrored configuration. followed by any number of storage devices that will comprise the mirror. Multiple mirrors can be specified by repeating the mirror keyword on the command line. with data being redundant between each disk appropriately. An RFE is filed for this feature. For more information about recommended mirrored configurations. Data is dynamically striped across both disks. see “Attaching and Detaching Devices in a Storage Pool” on page 87. For more information. Splitting a mirrored configuration by detaching one of the disks to create a new. Review the following root pool configuration information:
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.

The root pool cannot have a separate log device. but you can expand a mirrored virtual device by using the zpool attach command. For example:
# zpool create tank raidz2 c1t0d0 c2t0d0 c3t0d0 c4t0d0 c5t0d0 # zpool status -v tank pool: tank state: ONLINE scrub: none requested config: NAME tank raidz2-0 c1t0d0 c2t0d0 c3t0d0 c4t0d0 c5t0d0 STATE ONLINE ONLINE ONLINE ONLINE ONLINE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
errors: No known data errors
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. except that the raidz or raidz1 keyword is used instead of mirror. You cannot add additional disks to create multiple mirrored top-level virtual devices by using the zpool add command. you see messages similar to the following:
ERROR: ZFS pool <pool-name> does not support boot environments # zpool add -f rpool log c0t6d0s0 cannot add to ’rpool’: root pool can not have multiple vdevs or separate logs
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For more information about installing and booting a ZFS root file system. The following example shows how to create a pool with a single RAID-Z device that consists of five disks:
# zpool create tank raidz c1t0d0 c2t0d0 c3t0d0 c4t0d0 /dev/dsk/c5t0d0
This example illustrates that disks can be specified by using their shorthand device names or their full device names. If you attempt to use an unsupported configuration for a root pool. Both /dev/dsk/c5t0d0 and c5t0d0 refer to the same disk. “Managing ZFS Root Pool Components. A RAID-Z or a striped configuration is not supported.”
Creating a RAID-Z Storage Pool
Creating a single-parity RAID-Z pool is identical to creating a mirrored pool. and the pool must be created with disk slices. The root pool must be created as a mirrored configuration or as a single-disk configuration. see Chapter 5. You can create a double-parity or triple-parity RAID-Z configuration by using the raidz2 or raidz3 keyword when creating the pool.Creating and Destroying ZFS Storage Pools
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Disks used for the root pool must have a VTOC (SMI) label.

when you need to detach a spare disk. You cannot outright remove a device that is not a log or a cache device from a RAID-Z configuration. However. the following operations are not supported in a RAID-Z configuration:
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Attaching an additional disk to an existing RAID-Z configuration. see “RAID-Z Storage Pool Configuration” on page 71. the following operations are supported in a ZFS RAID-Z configuration:
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Adding another set of disks for an additional top-level virtual device to an existing RAID-Z configuration. except when you are detaching a disk that is replaced by a spare disk. better performance might be possible by using separate intent log devices.Creating and Destroying ZFS Storage Pools
# zpool create tank raidz3 c0t0d0 c1t0d0 c2t0d0 c3t0d0 c4t0d0 c5t0d0 c6t0d0 c7t0d0 # zpool status -v tank pool: tank state: ONLINE scrub: none requested config: NAME tank raidz3-0 c0t0d0 c1t0d0 c2t0d0 c3t0d0 c4t0d0 c5t0d0 c6t0d0 c7t0d0 STATE ONLINE ONLINE ONLINE ONLINE ONLINE ONLINE ONLINE ONLINE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
errors: No known data errors
Currently. the ZIL is allocated from blocks within the main pool. see “Setting Up Separate ZFS Log Devices” on page 39. An RFE is filed for this feature.
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Currently. For more information about ZFS log devices. Or.
Creating a ZFS Storage Pool With Log Devices
By default. Replacing a disk or disks in an existing RAID-Z configuration as long as the replacement disks are greater than or equal to the size of the device to be replaced. For more information. The following example shows how to create a mirrored storage pool with mirrored log devices:
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. such as NVRAM or a dedicated disk. For more information.
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For more information about a RAID-Z configuration. see “Adding Devices to a Storage Pool” on page 82. Detaching a disk from a RAID-Z configuration. see “Replacing Devices in a Storage Pool” on page 94. You can set up a ZFS log device when the storage pool is created or after the pool is created.

which might be part of a mirrored or a RAID-Z configuration. The content of the cache devices is considered volatile. known as a top-level vdev. As such. the configuration provide data redundancy as mirror or RAID-Z virtual devices. If the top-level virtual device contains two or more physical devices. Virtual devices and the physical devices that are contained in a ZFS storage pool are displayed with the zpool status command. A virtual device is an internal representation of the storage pool that describes the layout of physical storage and the storage pool's fault characteristics. These virtual devices consist of disks.
Displaying Storage Pool Virtual Device Information
Each storage pool contains one or more virtual devices. a virtual device represents the disk devices or files that are used to create the storage pool. Storage pools typically contain multiple top-level virtual devices. or files. For example:
# zpool pool: state: scrub: config: status tank tank ONLINE none requested NAME tank
78
STATE ONLINE
READ WRITE CKSUM 0 0 0
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.Creating and Destroying ZFS Storage Pools
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Cache devices cannot be mirrored or be part of a RAID-Z configuration. or files that are used in nonredundant pools function as top-level virtual devices. disk slices. A spare is a special virtual dev that tracks available hot spares for a pool. ZFS dynamically stripes data among all of the top-level virtual devices in a pool. disk slices. A pool can have any number of virtual devices at the top of the configuration. If a read error is encountered on a cache device. that read I/O is reissued to the original storage pool device. For example:
# zpool add mypool raidz2 c2d1 c3d1 c4d1 c5d1
Disks. each a mirror of two disks:
# zpool create tank mirror c1d0 c2d0 mirror c3d0 c4d0
The following example shows how to create pool that consists of one top-level virtual device of four disks:
# zpool create mypool raidz2 c1d0 c2d0 c3d0 c4d0
You can add another top-level virtual device to this pool by using the zpool add command. similar to other system caches. The following example shows how to create a pool that consists of two top-level virtual devices.

remove or comment out the line in the /etc/vfstab file. If the disk is in use.
Detecting In-Use Devices
Before formatting a device.Creating and Destroying ZFS Storage Pools
mirror-0 c0t1d0 c1t1d0 mirror-1 c0t2d0 c1t2d0 mirror-2 c0t3d0 c1t3d0
ONLINE ONLINE ONLINE ONLINE ONLINE ONLINE ONLINE ONLINE ONLINE
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
errors: No known data errors
Handling ZFS Storage Pool Creation Errors
Pool creation errors can occur for many reasons.
Dedicated dump device Part of a ZFS pool
The following in-use checks serve as helpful warnings and can be overridden by using the -f option to create the pool:
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. if it is no longer needed. while other reasons are more subtle. The disk or file is part of an active ZFS storage pool.
Some errors can be overridden by using the -f option. To correct this error. To correct this error. ZFS first determines if the disk is in-use by ZFS or some other part of the operating system. Please see swap(1M). Or. you might see errors such as the following:
# zpool create tank c1t0d0 c1t1d0 invalid vdev specification use ’-f’ to override the following errors: /dev/dsk/c1t0d0s0 is currently mounted on /. The following conditions cannot be overridden by using the -f option. Please see umount(1M). Some reasons are obvious. use the zpool destroy command to destroy the other pool. Please see zpool(1M). use the zpool detach command to detach the disk from the other pool. You can only detach a disk from a mirrored storage pool. /dev/dsk/c1t0d0s1 is currently mounted on swap. /dev/dsk/c1t1d0s0 is part of active ZFS pool zeepool. and you must manually correct them: Mounted file system File system in /etc/vfstab The disk or one of its slices contains a file system that is currently mounted. use the umount command. but the file system is not currently mounted. such as when a specified device doesn't exist. but most errors cannot. To correct this error. The disk contains a file system that is listed in the /etc/vfstab file. The disk is in use as the dedicated dump device for the system. To correct this error. use the dumpadm command.

though it is not mounted and doesn't appear to be in use. Although this configuration is allowed. If you try to create a pool with such a configuration.
Mismatched Replication Levels
Creating pools with virtual devices of different replication levels is not recommended. This dry run option performs the device in-use checking and replication-level validation.
Doing a Dry Run of Storage Pool Creation
Attempts to create a pool can fail unexpectedly in different ways. which simulates creating the pool without actually writing to the device. The -f option is required to override the warning. but you should avoid this practice. you see output similar to the following:
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. The zpool command tries to prevent you from accidentally creating a pool with mismatched levels of redundancy. the pool is reported as potentially active. -n. The command also warns you about creating a mirrored or RAID-Z pool using devices of different sizes. mismatched levels of redundancy result in unused disk space on the larger device. and reports any errors in the process. For these reasons. the zpool create command has an additional option. The disk is part of a storage pool that has been exported or manually removed from a system. The disk is part of a Solaris Volume Manager volume.
The following example demonstrates how the -f option is used:
# zpool create tank c1t0d0 invalid vdev specification use ’-f’ to override the following errors: /dev/dsk/c1t0d0s0 contains a ufs filesystem.Creating and Destroying ZFS Storage Pools
Contains a file system Part of volume Part of exported ZFS pool
The disk contains a known file system. In the latter case. If no errors are found. correct the errors rather than use the -f option to override them. # zpool create -f tank c1t0d0
Ideally. as the disk might or might not be a network-attached drive in use by another system. and formatting disks is a potentially harmful action. you see errors similar to the following:
# zpool create tank c1t0d0 mirror c2t0d0 c3t0d0 invalid vdev specification use ’-f’ to override the following errors: mismatched replication level: both disk and mirror vdevs are present # zpool create tank mirror c1t0d0 c2t0d0 mirror c3t0d0 c4t0d0 c5t0d0 invalid vdev specification use ’-f’ to override the following errors: mismatched replication level: 2-way mirror and 3-way mirror vdevs are present
You can override these errors with the -f option. Be cautious when overriding a potentially active pool.

so the zpool create -n command can report success and yet fail to create the pool when the command is run without this option. use the -m option of the zpool create command.
Default Mount Point for Storage Pools
When a pool is created. The most common example is specifying the same device twice in the same configuration. see “Recovering Destroyed ZFS Storage Pools” on page 121. you can attempt to recover the pool. If the directory does not exist. This command destroys the pool even if it contains mounted datasets. For more information. it is automatically created. This directory must either not exist or be empty. This error cannot be reliably detected without actually writing the data. To create a pool with a different default mount point. see “Managing ZFS Mount Points” on page 174.
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. For more information about mount points. If you accidentally destroy the wrong pool.
Destroying ZFS Storage Pools
Pools are destroyed by using the zpool destroy command. the root dataset is mounted on top of the existing directory.
# zpool destroy tank Caution – Be very careful when you destroy a pool.Creating and Destroying ZFS Storage Pools
# zpool create -n tank mirror c1t0d0 c1t1d0 would create ’tank’ with the following layout: tank mirror c1t0d0 c1t1d0
Some errors cannot be detected without actually creating the pool. For example:
# zpool create home c1t0d0 default mountpoint ’/home’ exists and is not empty use ’-m’ option to provide a different default # zpool create -m /export/zfs home c1t0d0
This command creates the new pool home and the home dataset with a mount point of /export/zfs. Ensure that you are destroying the right pool and you always have copies of your data. If the directory is empty. the default mount point for the top-level dataset is /pool-name.

you can perform several tasks to manage the physical devices within the pool. so whether data is stored there is unknown. If one or more devices are unavailable. For example:
# zpool destroy tank cannot destroy ’tank’: pool is faulted use ’-f’ to force destruction anyway # zpool destroy -f tank
For more information about pool and device health. To add a new virtual device to a pool.Managing Devices in ZFS Storage Pools
Destroying a Pool With Faulted Devices
The act of destroying a pool requires data to be written to disk to indicate that the pool is no longer valid. the necessary state information won't be written to these unavailable devices. For more information about importing pools. However. when suitably repaired. If a pool has enough faulted devices such that the pool itself is faulted (meaning that a top-level virtual device is faulted). They appear as valid devices when you search for pools to import. use the zpool add command. This disk space is immediately available to all datasets in the pool. see “Determining the Health Status of ZFS Storage Pools” on page 111.
Managing Devices in ZFS Storage Pools
Most of the basic information regarding devices is covered in “Components of a ZFS Storage Pool” on page 67. the pool can still be destroyed. These devices. then the command prints a warning and cannot complete without the -f option. see “Importing ZFS Storage Pools” on page 118.
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“Adding Devices to a Storage Pool” on page 82 “Attaching and Detaching Devices in a Storage Pool” on page 87 “Creating a New Pool By Splitting a Mirrored ZFS Storage Pool” on page 89 “Onlining and Offlining Devices in a Storage Pool” on page 92 “Clearing Storage Pool Device Errors” on page 94 “Replacing Devices in a Storage Pool” on page 94 “Designating Hot Spares in Your Storage Pool” on page 96
Adding Devices to a Storage Pool
You can dynamically add disk space to a pool by adding a new top-level virtual device. This option is necessary because the pool cannot be opened. After a pool has been created. are reported as potentially active when you create a new pool. This state information prevents the devices from showing up as a potential pool when you perform an import. For example:
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.

a zpool split operation on a mirrored pool detaches the last disk for the newly created pool. After the split operation. You can use the zpool split command to detach disks from a mirrored ZFS storage pool to create a new pool with one of the detached disks. this operation fails if no other valid replicas of the data exist. By default. import the new pool. For example:
# zpool pool: state: scrub: config: status tank tank ONLINE none requested NAME tank mirror-0 c1t0d0 c1t2d0 errors: # zpool # zpool # zpool pool: STATE ONLINE ONLINE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0 0 0 0 0 0 0
No known data errors split tank tank2 import tank2 status tank tank2 tank
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. For example:
# zpool detach newpool c1t2d0 cannot detach c1t2d0: only applicable to mirror and replacing vdevs
Creating a New Pool By Splitting a Mirrored ZFS Storage Pool
A mirrored ZFS storage pool can be quickly cloned as a backup pool by using the zpool split command.Managing Devices in ZFS Storage Pools
EXAMPLE 4–6
Converting a Nonredundant ZFS Storage Pool to a Mirrored ZFS Storage Pool
(Continued)
errors: No known data errors
You can use the zpool detach command to detach a device from a mirrored storage pool. For example:
# zpool detach zeepool c2t1d0
However. Currently. this feature cannot be used to split a mirrored root pool. The new pool will have identical contents to the original mirrored ZFS storage pool.

Review the following considerations before using the zpool split feature:
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This feature is not available for a RAIDZ configuration or a non-redundant pool of multiple disks. then you will need to use the zpool split -R option to identify an alternate root directory for the new pool so that any existing mount points do not conflict. Data and application operations should be quiesced before attempting a zpool split operation. the disk's flush write cache command is important. After the data is flushed. If the new pool is created on a different system. For example:
# zpool split tank tank2 c1t0d0
Before the actual split operation occurs. the disk is detached from the pool and given a new pool GUID. import the new pool with the -R option. rather than ignore. For example:
# zpool split -R /tank2 tank tank2
If you don't use the zpool split -R option and you can see that mount points conflict when you attempt to import the new pool. then specifying an alternate root directory should not be necessary unless mount point conflicts occur. data in memory is flushed to the mirrored disks. A new pool GUID is generated so that the pool can be imported on the same system on which it was split. A pool cannot be split if resilvering is in process.
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. If the pool to be split has non-default dataset mount points and the new pool is created on the same system. Having disks that honor.Managing Devices in ZFS Storage Pools
state: ONLINE scrub: none requested config: NAME tank c1t0d0 STATE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0
errors: No known data errors pool: tank2 state: ONLINE scrub: none requested config: NAME tank2 c1t2d0 STATE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0
errors: No known data errors
You can identify which disk should be used for the newly created pool by specifying it with the zpool split command.

where the last disk in the original pool is used for the newly created pool. If the existing pool is a three-way mirror. Each pool has identical content. with three disks. A good way to keep your data redundant during a split operation is to split a mirrored storage pool that is composed of three disks so that the original pool is comprised of two mirrored disks after the split operation. Then. You will need to attach two additional disks to convert the non-redundant pools to mirrored pools.Managing Devices in ZFS Storage Pools
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Splitting a mirrored pool is optimal when composed of two to three disks.
# zpool pool: state: scrub: config: status trinity trinity ONLINE none requested NAME trinity mirror-0 c1t0d0 c1t2d0 c1t3d0 errors: # zpool # zpool # zpool pool: state: scrub: config: STATE ONLINE ONLINE ONLINE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
No known data errors split trinity neo import neo status trinity neo neo ONLINE none requested NAME neo c1t3d0 STATE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0
errors: No known data errors pool: trinity state: ONLINE scrub: none requested config:
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. with disk c1t3d0. c1t0d0. then the new pool will contain one disk after the split operation. neo. then the outcome is two non-redundant pools of two disks. you can use the zpool attach command to recreate your original mirrored storage pool or convert your newly created pool into a mirrored storage pool. If the existing pool is a two-way mirror of two disks. with disks c1t0d0 and c1t2d0. No way currently exists to create a new mirrored pool from an existing mirrored pool by using this feature. The two resulting pools are the mirrored pool trinity. and the new pool. c1t2d0 and c1t3d0 is split.
Splitting a Mirrored ZFS Pool
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EXAMPLE 4–7
In the following example. a mirrored storage pool called trinity.

if the device is a disk.
Note – Devices do not need to be taken offline in order to replace them. For example. The device remains offline when the system is rebooted.
Taking a Device Offline
You can take a device offline by using the zpool offline command.
# zpool offline tank c1t0d0 cannot offline c1t0d0: no valid replicas
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By default. For example:
# zpool offline tank c1t0d0 bringing device c1t0d0 offline
Consider the following points when taking a device offline:
■
You cannot take a pool offline to the point where it becomes faulted. you cannot take offline two devices in a raidz1 configuration. nor can you take offline a top-level virtual device. When hardware is unreliable or not functioning properly. If the condition is not temporary. the OFFLINE state is persistent. assuming the condition is only temporary. this device is automatically returned to the ONLINE state. ZFS does not send any requests to an offline device. To temporarily take a device offline. The device can be specified by path or by short name. use the zpool offline -t option. ZFS continues to read data from or write data to the device. For example:
# zpool offline -t tank c1t0d0 bringing device ’c1t0d0’ offline
When the system is rebooted.
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.Managing Devices in ZFS Storage Pools
EXAMPLE 4–7
Splitting a Mirrored ZFS Pool STATE ONLINE ONLINE ONLINE ONLINE
(Continued)
NAME trinity mirror-0 c1t0d0 c1t2d0
READ WRITE CKSUM 0 0 0 0 0 0 0 0 0 0 0 0
errors: No known data errors
Onlining and Offlining Devices in a Storage Pool
ZFS allows individual devices to be taken offline or brought online. you can instruct ZFS to ignore the device by taking it offline.

then destroy the original storage pool.0 EVENT-ID: 504a1188-b270-4ab0-af4e-8a77680576b8 DESC: A ZFS device failed.Sun-Fire-880. while keeping the original storage pool. For information about replacing devices. HOSTNAME: neo SOURCE: zfs-diagnosis.
Bringing a Device Online
After a device is taken offline. it is not detached from the storage pool. you see a message similar to the following:
device is part of exported or potentially active ZFS pool. If you take a device offline. SEVERITY: Major EVENT-TIME: Wed Jun 30 14:53:39 MDT 2010 PLATFORM: SUNW. For information about querying pool status. VER: 1. Another way to use a device from another storage pool. CSN: -.Managing Devices in ZFS Storage Pools
■
When a device is taken offline. and try to bring it online. Note that you cannot use bring a device online to replace a disk. REV: 1. see “Querying ZFS Storage Pool Status” on page 105. it remains in the faulted state.com/msg/ZFS-8000-D3 for more information. For more information on device health. a message similar to the following is displayed:
# zpool online tank c1t0d0 warning: device ’c1t0d0’ onlined. TYPE: Fault. If you attempt to use the offline device in another pool. even after the original pool is destroyed. Refer to http://sun. but remains in faulted state use ’zpool replace’ to replace devices that are no longer present
You might also see the faulted disk message displayed on the console or written to the /var/adm/messages file. AUTO-RESPONSE: No automated response will occur. any data that has been written to the pool is resynchronized with the newly available device. it can be brought online again by using the zpool online command. replace the device. see “Determining the Health Status of ZFS Storage Pools” on page 111. see “Replacing Devices in a Storage Pool” on page 94. For example:
# zpool online tank c1t0d0 bringing device c1t0d0 online
When a device is brought online.
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. If you attempt to bring online a faulted device. Offline devices are in the OFFLINE state when you query pool status. For example:
SUNW-MSG-ID: ZFS-8000-D3. is to replace the existing device in the original storage pool with another comparable device. first bring the device online. Please see zpool(1M)
If you want to use the offline device in another storage pool after destroying the original storage pool.

If specified with no arguments. this command clears all device errors within the pool. you will need to specify both devices.
Replacing Devices in a Storage Pool
You can replace a device in a storage pool by using the zpool replace command. you can clear the error counts with the zpool clear command. REC-ACTION: Run ’zpool status -x’ and replace the bad device. For example:
# zpool online -e tank c1t13d0
Clearing Storage Pool Device Errors
If a device is taken offline due to a failure that causes errors to be listed in the zpool status output. to replace a failed disk (c1t1d0) by removing the disk and replacing it in the same location. For example:
# zpool clear tank c1t0d0
For more information about clearing zpool errors. then you might only need to identify the replaced device. For example. By default. see “Clearing Transient Errors” on page 276. a LUN that is added to a pool is not expanded to its full size unless the autoexpand pool property is enabled. use the following syntax:
# zpool replace tank c1t1d0
If you are replacing a device in a storage pool with a disk in a different physical location. You can expand the LUN automatically by using the zpool online -ecommand even if the LUN is already online or if the LUN is currently offline. For example:
# zpool replace tank c1t1d0 c1t2d0
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. For example:
# zpool clear tank
If one or more devices are specified.
For more information about replacing a faulted device. this command only clear errors associated with the specified devices. see “Resolving a Missing Device” on page 272. You can use the zpool online -e command to expand a LUN.Managing Devices in ZFS Storage Pools
IMPACT: Fault tolerance of the pool may be compromised. ZFS recognizes that the device is a different disk in the same location on some hardware. If you are physically replacing a device with another device in the same location in a redundant pool.

You are not required to use the zpool replace command when this property is enabled. you must unconfigure a disk before you can take it offline.
# zpool create pool mirror c1t16d0 c1t17d0 # zpool status pool: pool state: ONLINE scrub: none requested config: NAME pool mirror c1t16d0 STATE ONLINE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0 0 0 0
■
■
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. see Example 11–1. The following are the basic steps for replacing a disk:
■ ■ ■ ■
Offline the disk. if necessary. Run the zpool replace command. The autoexpand pool property value determines whether a replacement LUN is expanded to its full size when the disk is added to the pool. In the following example. then any new device found in the same physical location as a device that previously belonged to the pool is automatically formatted and replaced. If you are replacing a disk in the same slot position on this system. two 16-GB disks in a mirrored pool are replaced with two 72-GB disks. Consider the following when replacing devices in a ZFS storage pool:
■
If you set the autoreplace pool property to on. This feature might not be available on all hardware types. with the zpool offline command. see “How to Replace a Disk in the ZFS Root Pool” on page 138. then you can just run the zpool replace command as described in the first example in this section. such as the Sun Fire x4500. For an example of replacing a disk on a Sun Fire X4500 system. Remove the disk to be replaced. For example:
# zpool replace tank c1t1d0
■
Bring the disk online with the zpool online command. The autoexpand property is enabled after the disk replacements to expand the full LUN sizes. The size of the replacement device must be equal to or larger than the smallest disk in a mirrored or RAID-Z configuration. Insert the replacement disk. By default.
On some systems. When a replacement device that is greater in size than the device it is replacing is added to a pool. is not automatically expanded to its full size. You can enable this property to expand LUN size before or after the larger LUN is added to the pool. the autoexpand property is disabled.Managing Devices in ZFS Storage Pools
If you are replacing a disk in the ZFS root pool.

After the pool is created with the zpool add command. In addition. but if an active device in the pool fails. For information about detaching a hot spare. Designating a device as a hot spare means that the device is not an active device in the pool.5K 16.5K 16. the hot spare automatically replaces the failed device. If a failed disk has been replaced automatically with a hot spare.
Designating Hot Spares in Your Storage Pool
The hot spares feature enables you to identify disks that could be used to replace a failed or faulted device in one or more storage pools. You can use the zpool detach command to detach a spare in a mirrored or RAIDZ pool.Managing Devices in ZFS Storage Pools
c1t17d0 ONLINE
0
0
0 ALTROOT -
zpool list pool NAME SIZE ALLOC FREE CAP HEALTH pool 16.8G 76.
The following example shows how to designate devices as hot spares when the pool is created:
# zpool create trinity mirror c1t1d0 c2t1d0 spare c1t2d0 c2t2d0 # zpool status trinity pool: trinity state: ONLINE scrub: none requested config: NAME trinity
96
STATE ONLINE
READ WRITE CKSUM 0 0 0
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.2G 117K 68. you might consider running the zpool scrub command between disk replacements to ensure that the replacement devices are operational and that the data is written correctly.7G 0% ONLINE # zpool set autoexpand=on pool # zpool list pool NAME SIZE ALLOC FREE CAP HEALTH pool 68. Devices can be designated as hot spares in the following ways:
■ ■
When the pool is created with the zpool create command.7G 0% ONLINE # zpool replace pool c1t16d0 c1t1d0 # zpool replace pool c1t17d0 c1t2d0 # zpool list pool NAME SIZE ALLOC FREE CAP HEALTH pool 16.2G 0% ONLINE
■
ALTROOT ALTROOT -
Replacing many disks in a large pool is time-consuming due to resilvering the data onto the new disks.
■
For more information about replacing devices.8G 88. then you might need to detach the spare after the failed disk is replaced. see “Activating and Deactivating Hot Spares in Your Storage Pool” on page 98. see “Resolving a Missing Device” on page 272 and “Replacing or Repairing a Damaged Device” on page 274.

when the smaller spare disk is activated. Automatic replacement – When a fault is detected. If a hot spare that is currently in use fails. However. cache devices. See Example 4–8. you can reactivate the original device by using the zpool detach command to detach the spare. This feature is currently limited by the fact that the ZFS diagnostic engine only generates faults when a device disappears from the system.com/msg/ZFS-8000-2Q scrub: resilver completed after 0h0m with 0 errors on Mon Jan 11 10:20:35 2010 config: NAME zeepool mirror-0 c1t2d0 spare-1 c2t1d0 STATE READ WRITE CKSUM DEGRADED 0 0 0 DEGRADED 0 0 0 ONLINE 0 0 0 DEGRADED 0 0 0 UNAVAIL 0 0 0 cannot open
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. an FMA agent examines the pool to determine if it has any available hot spares. the operation fails with an error similar to the following:
cannot replace disk3 with disk4: device is too small
■
Activating and Deactivating Hot Spares in Your Storage Pool
Hot spares are activated in the following ways:
■
Manual replacement – You replace a failed device in a storage pool with a hot spare by using the zpool replace command. To add a disk as a hot spare. it replaces the faulted device with an available spare. Sufficient replicas exist for the pool to continue functioning in a degraded state. and log devices. the zpool remove command can only be used to remove hot spares. For example:
# zpool pool: state: status: status -x zeepool DEGRADED One or more devices could not be opened. If so.Managing Devices in ZFS Storage Pools
■
Currently. The agent then attempts to replace the device with another hot spare. If you set the autoreplace pool property to on. the hot spare must be equal to or larger than the size of the largest disk in the pool. the FMA agent detaches the spare and thereby cancels the replacement. If you physically replace a failed device with an active spare. either automatically or with the zpool replace command. if one is available.
■
You can manually replace a device with a hot spare by using the zpool replace command. the spare is automatically detached and returned to the spare pool when the new device is inserted and the online operation completes.sun. A faulted device is automatically replaced if a hot spare is available. Adding a smaller disk as a spare to a pool is allowed. see: http://www. action: Attach the missing device and online it using ’zpool online’.

If set to off. or in an alternate boot environment. if the mount points cannot be trusted. For example:
# zpool NAME zeepool zeepool zeepool zeepool zeepool zeepool zeepool zeepool zeepool zeepool zeepool zeepool zeepool zeepool zeepool zeepool zeepool zeepool get all zeepool PROPERTY size capacity altroot health guid version bootfs delegation autoreplace cachefile failmode listsnapshots autoexpand dedupditto dedupratio free allocated readonly VALUE SOURCE 33.00x 33. If set. Identifies an alternate root directory. This property can be used when you are examining an unknown pool.8G 0% default ONLINE 8588873752016230819 default 31 default default on default off default default wait default off default off default 0 default 1. where the typical paths are not valid. this directory is prepended to any mount points within the pool.Managing ZFS Storage Pool Properties
Managing ZFS Storage Pool Properties
You can use the zpool get command to display pool property information.
altroot
autoreplace
Boolean
off
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. Controls automatic device replacement. device replacement must be initiated by using the zpool replace command.7G 104K off -
Storage pool properties can be set with the zpool set command. For example:
# zpool # zpool NAME zeepool
TABLE 4–1
set autoreplace=on zeepool get autoreplace zeepool PROPERTY VALUE SOURCE autoreplace on local ZFS Pool Property Descriptions
Type Default Value Description
Property Name
allocated
String String
N/A off
Read-only value that identifies the amount of storage space within the pool that has been physically allocated. any new device found in the same physical location as a device that previously belonged to the pool is automatically formatted and replaced. If set to on. The property abbreviation is replace.

For more information.Managing ZFS Storage Pool Properties
TABLE 4–1
ZFS Pool Property Descriptions
Type Default Value
(Continued)
Description
Property Name
bootfs
Boolean
N/A
Identifies the default bootable dataset for the root pool. this property is not used.”
dedupratio
String Boolean
N/A on
delegation
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. This information can be imported later by using the zpool import -c command. Read-only deduplication ratio achieved for a pool. and if the reference count for a deduped block goes above the threshold. Read-only value that identifies the percentage of pool space used. “Oracle Solaris ZFS Delegated Administration. expressed as a multiplier. Controls where pool configuration information is cached. This property is typically set by the installation and upgrade programs. The property abbreviation is cap. However. All pools in the cache are automatically imported when the system boots. see Chapter 9. You can set this property to cache pool configuration information in a different location. Controls whether a nonprivileged user can be granted access permissions that are defined for a dataset. For most ZFS configurations. another ditto copy of the block is stored automatically. installation and clustering environments might require this information to be cached in a different location so that pools are not automatically imported.
cachefile
String
N/A
capacity
Number
N/A
dedupditto
String
N/A
Sets a threshold.

or UNAVAIL. but allows reads to any of the remaining healthy devices. This property is only enabled when a pool is has been imported in read-only mode. Any write requests that have yet to be committed to disk are blocked. If this property is disabled. panic – Prints a message to the console and generates a system crash dump. After the device is reconnected or replaced. the errors must be cleared with the zpool clear command. any synchronous data that exists only in the intent log will not be accessible until the pool is re-imported in read-write mode. The behavior of such an event is determined by one of the following values: ■ wait – Blocks all I/O requests to the pool until device connectivity is restored.
■
free
String String String
N/A N/A N/A
Read-only value that identifies the number of blocks within the pool that are not allocated.
■
continue – Returns an EIO error to any new write I/O requests.Managing ZFS Storage Pool Properties
TABLE 4–1
ZFS Pool Property Descriptions
Type Default Value
(Continued)
Description
Property Name
failmode
String
wait
Controls the system behavior if a catastrophic pool failure occurs. I/O operations to the pool are blocked. This condition is typically a result of a loss of connectivity to the underlying storage device or devices or a failure of all devices within the pool. REMOVED. but read operations might succeed. and the errors are cleared by using the zpool clear command. DEGRADED. In this state. Read-only property that identifies the total size of the storage pool. as either ONLINE.
guid
health
listsnapshots
String
off
readonly
Boolean
off
size
Number
N/A
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. Read-only property that identifies the current health of the pool. Identifies whether a pool can be modified. OFFLINE. FAULTED. If enabled. Controls whether snapshot information that is associated with this pool is displayed with the zfs list command. Read-only property that identifies the unique identifier for the pool. snapshot information can be displayed with the zfs list -t snapshot command. A pool remains in the wait state until the device issue is resolved.

0G 1. and health status. All three types of storage pool information are covered in this section. The information available generally falls into three categories: basic usage information. I/O statistics.2T ALLOC FREE 22. equal to the sum of the sizes of all top-level virtual devices. The total size of the pool. the zpool listcommand displays the following information for all pools on the system:
# zpool list NAME tank dozer SIZE 80. For more information about determining available file system space. The amount of physical space allocated to all datasets and internal metadata. although this property can be used when a specific version is needed for backwards compatibility.
Listing Information About All Storage Pools or a Specific Pool
With no arguments. Note that this amount differs from the amount of disk space as reported at the file system level.Querying ZFS Storage Pool Status
TABLE 4–1
ZFS Pool Property Descriptions
Type Default Value
(Continued)
Description
Property Name
version
Number
N/A
Identifies the current on-disk version of the pool. This property can be set to any number between 1 and the current version reported by the zpool upgrade -v command.7G 384G 816G CAP HEALTH 28% ONLINE 32% ONLINE ALTROOT -
This command output displays the following information: NAME SIZE ALLOC The name of the pool. The preferred method of updating pools is with the zpool upgrade command.
Querying ZFS Storage Pool Status
The zpool list command provides several ways to request information regarding pool status.3G 47.
■ ■ ■
“Displaying Information About ZFS Storage Pools” on page 105 “Viewing I/O Statistics for ZFS Storage Pools ” on page 109 “Determining the Health Status of ZFS Storage Pools” on page 111
Displaying Information About ZFS Storage Pools
You can use the zpool list command to display basic information about pools.
Chapter 4 • Managing Oracle Solaris ZFS Storage Pools 105
. see “ZFS Disk Space Accounting” on page 64.

to list only the name and size of each pool. The current health status of the pool. if one exists.7G 0% 1.00x ONLINE 21.
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. The amount of disk space used.8G 12. For more information about pool health. you can display a time stamp by using the -T option.00x ONLINE MDT 2010 33.7G CAP HEALTH 28% ONLINE ALTROOT -
You can use the zpool list interval and count options to gather statistics over a period of time. expressed as a percentage of the total disk space. For more information about alternate root pools.7G 0% 1.2G Tue Nov 2 10:36:14 pool 33. For example.2T
The column names correspond to the properties that are listed in “Listing Information About All Storage Pools or a Specific Pool” on page 105. see “Determining the Health Status of ZFS Storage Pools” on page 111.8G 12. This option provides custom reports or a quick way to list pertinent information.2G 2 MDT 2010 FREE CAP DEDUP HEALTH ALTROOT 33. In addition.8G 83.5K rpool 33.00x ONLINE -
Listing Specific Storage Pool Statistics
Specific statistics can be requested by using the -o option.8G 83.
ALTROOT
The alternate root of the pool.5K rpool 33.size NAME SIZE tank 80. you use the following syntax:
# zpool list -o name. see “Using ZFS Alternate Root Pools” on page 261.0G dozer 1.5G 36% 1.00x ONLINE 21.0G ALLOC 22.5G 36% 1.
You can also gather statistics for a specific pool by specifying the pool name. For example:
# zpool list -T d 3 Tue Nov 2 10:36:11 NAME SIZE ALLOC pool 33.3G FREE 47. For example:
# zpool list tank NAME tank SIZE 80.Querying ZFS Storage Pool Status
FREE CAP (CAPACITY) HEALTH
The amount of unallocated space in the pool.

For example.10:18:54 zpool create -f -o failmode=continue -R /a -m legacy -o cachefile=/tmp/root/etc/zfs/zpool.10:19:03 zfs set canmount=on rpool 2010-05-11.10:18:55 zfs set canmount=noauto rpool 2010-05-11.10:19:04 zfs create -o mountpoint=/export rpool/export 2010-05-11. The log is saved persistently on disk.11:11:10 zpool set bootfs=rpool/ROOT/zfsBE rpool
You can use similar output on your system to identify the actual ZFS commands that were executed to troubleshoot an error condition.10:18:56 zfs create -o mountpoint=legacy rpool/ROOT 2010-05-11.10:18:58 zfs create -b 131072 -V 1536m rpool/dump 2010-05-11.
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.Querying ZFS Storage Pool Status
Scripting ZFS Storage Pool Output
The default output for the zpool list command is designed for readability and is not easy to use as part of a shell script. you would use the following syntax:
# zpool list -Ho name tank dozer
Here is another example:
# zpool list -H -o name.10:19:02 zpool set bootfs=rpool/ROOT/zfsBE rpool 2010-05-11. which means that the log is saved across system reboots. The features of the history log are as follows:
■ ■
The log cannot be disabled.10:18:55 zfs set mountpoint=/rpool rpool 2010-05-11. This information can be displayed by using the zpool history command.10:19:02 zfs set mountpoint=/ rpool/ROOT/zfsBE 2010-05-11.2T
Displaying ZFS Storage Pool Command History
ZFS automatically logs successful zfs and zpool commands that modify pool state information. For example.0G dozer 1.10:19:05 zfs create rpool/export/home 2010-05-11.size tank 80.10:19:01 zfs create -o canmount=noauto rpool/ROOT/zfsBE 2010-05-11.cache rpool mirror c1t0d0s0 c1t1d0s0 2010-05-11.11:11:10 zpool set bootfs=rpool rpool 2010-05-11. to request a list of all pool names on the system. rather than by spaces. the -H option can be used to suppress the column headings and separate fields by tabs.10:18:57 zfs create -b 8192 -V 2048m rpool/swap 2010-05-11. the following syntax displays the command output for the root pool:
# zpool history History for ’rpool’: 2010-05-11. To aid programmatic uses of the command.

expressed as units per second.7M
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. This amount differs from the amount of disk space available to actual file systems by a small margin due to internal implementation details. The bandwidth of all read operations (including metadata). see “ZFS Disk Space Accounting” on page 64.-----
Because these statistics are cumulative since boot. this amount differs from the amount of disk space available to datasets by a small margin.----6.5G 49. the zpool iostat command displays the accumulated statistics since boot for all pools on the system. As with the used statistic.----.
read operations write operations read bandwidth write bandwidth
Listing Pool-Wide I/O Statistics
With no options.----.----. bandwidth might appear low if the pool is relatively idle.05G 61.5G 0 464 0 57. use the zpool iostat command.----. For example:
# zpool iostat tank 2 capacity operations bandwidth pool alloc free read write read write ---------. The following statistics are reported: alloc capacity The amount of data currently stored in the pool or device. For example:
# zpool iostat pool ---------rpool tank ---------capacity operations bandwidth alloc free read write read write ----.----.7G 4 1 296K 86.----.----. The number of write I/O operations sent to the pool or device.9G 0 0 786 107 31. this command can display a static snapshot of all I/O activity. You can request a more accurate view of current bandwidth usage by specifying an interval. as well as updated statistics for every specified interval. including metadata requests. The number of read I/O operations sent to the pool or device. Similar to the iostat command.Querying ZFS Storage Pool Status
Viewing I/O Statistics for ZFS Storage Pools
To request I/O statistics for a pool or specific virtual devices. free capacity The amount of disk space available in the pool or device.3G 36.----tank 18.5G 0 187 0 23. For more information about the differences between pool space and dataset space.----.----.----.5G 49. expressed as units per second.----.1K ----. The bandwidth of all write operations.----.----.3M tank 18.

which causes the command to terminate after the specified number of iterations. broken. The way in which disk space is allocated among mirror and RAID-Z virtual devices is particular to the implementation and not easily expressed as a single number.----.05G 61. the command displays usage statistics for the pool tank every two seconds until you type Control-C.
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. which is not accounted for at the mirror level. or offline devices can affect this symmetry as well.----.5G 126 45 8. In particular.01M c1t2d0 0 3 100K 386K c1t3d0 0 3 104K 386K ---------. Alternately.9G 0 0 785 107 mirror 6.----.----. For example.5G 31. then an additional dashed line delineates each iteration to provide visual separation. for a total of six seconds.-----
Note two important points when viewing I/O statistics for virtual devices:
■
First. use the zpool iostat -v command.----.5G 4 1 295K 146K mirror 36.----.Querying ZFS Storage Pool Status
tank tank
18. If there is only a single pool. However.5G 49. unresponsive.----.----.----. you can specify an additional count argument.----rpool 6. operations across RAID-Z and mirrored devices will not be exactly equal.
■
You can use the same set of options (interval and count) when examining virtual device statistics.----tank 36. disk space usage statistics are only available for top-level virtual devices. This command can be used to identify abnormally slow devices or to observe the distribution of I/O generated by ZFS. Over time.13M 4.5G 31. For example:
# zpool iostat -v capacity operations bandwidth pool alloc free read write read write ---------. then the statistics are displayed on consecutive lines. zpool iostat 2 3 would print a summary every two seconds for three iterations.6M 0 51.----.
Listing Virtual Device I/O Statistics
In addition to pool-wide I/O statistics. the numbers might not add up exactly as you would expect them to.----.05G 61. as a significant amount of I/O is done directly to the disks as part of pool creation. these numbers gradually equalize. This difference is particularly noticeable immediately after a pool is created. the zpool iostat command can display I/O statistics for virtual devices. Second. If more than one pool exists.9G 0 0 785 107 c1t0d0s0 0 0 578 109 c1t1d0s0 0 0 595 109 ---------.----.----.2G
0 0
457 435
0 56. To request the complete virtual device layout as well as all I/O statistics.5G 18.----.8G 49.----.3M
In this example.

The health of a pool is determined from the state of all its devices. then the pool is also FAULTED. then the pool is also DEGRADED. If any one of the virtual devices is DEGRADED or UNAVAIL. then the pool is also ONLINE. If a top-level virtual device is FAULTED or OFFLINE. such that ZFS is incapable of sending data to it or receiving data from it. For more information about troubleshooting and data recovery. This section describes how to determine pool and device health. This chapter does not document how to repair or recover from unhealthy pools. No data can be recovered until the necessary devices are attached or repaired. The fault tolerance of the pool might be compromised. The virtual device has experienced a failure but can still function.Querying ZFS Storage Pool Status
Determining the Health Status of ZFS Storage Pools
ZFS provides an integrated method of examining pool and device health. displayed on the system console. A pool in the FAULTED state is completely inaccessible. A pool in the DEGRADED state continues to run. If a top-level virtual device is UNAVAIL. This status typically indicates total failure of the device. In addition. If a top-level virtual device is in this state. then the pool is completely inaccessible. This state is most common when a mirror or RAID-Z device has lost one or more constituent devices. potential pool and device failures are reported by fmd. pools with UNAVAIL devices appear in DEGRADED mode. then nothing in the pool can be accessed. see Chapter 11.” Each device can fall into one of the following states: ONLINE DEGRADED The device or virtual device is in normal working order.
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. If all virtual devices are ONLINE. Device removal detection is hardware-dependent and might not be supported on all platforms. The device was physically removed while the system was running. In some cases. The device or virtual device cannot be opened. The device or virtual device is completely inaccessible. The device has been explicitly taken offline by the administrator. the device is otherwise in working order. Although some transient errors might still occur. “Oracle Solaris ZFS Troubleshooting and Pool Recovery. and logged in the /var/adm/messages file.
FAULTED
OFFLINE UNAVAIL
REMOVED
The health of a pool is determined from the health of all its top-level virtual devices. This state information is displayed by using the zpool status command. but you might not achieve the same level of data redundancy or data throughput than if the pool were online. as a subsequent fault in another device might be unrecoverable.

as described in the next section.com/msg/ZFS-8000-2Q scrub: scrub completed after 0h0m with 0 errors on Wed Jan 20 15:13:59 2010 config: NAME tank mirror-0 c1t0d0 c1t1d0 STATE READ WRITE CKSUM DEGRADED 0 0 0 DEGRADED 0 0 0 ONLINE 0 0 0 UNAVAIL 0 0 0 cannot open
errors: No known data errors
This output displays a complete description of why the pool is in its current state. see: http://www. including a readable description of the problem and a link to a knowledge article for more information. If a pool has an offline device. After the device is replaced. For example:
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. Using the detailed configuration information.sun. For example:
# zpool pool: state: status: status -v tank tank DEGRADED One or more devices could not be opened. action: Attach the missing device and online it using ’zpool online’. Sufficient replicas exist for the pool to continue functioning in a degraded state. Each knowledge article provides up-to-date information about the best way to recover from your current problem. use the zpool online command to bring the device online.Querying ZFS Storage Pool Status
Basic Storage Pool Health Status
You can quickly review pool health status by using the zpool status command as follows:
# zpool status -x all pools are healthy
Specific pools can be examined by specifying a pool name in the command syntax. you can determine which device is damaged and how to repair the pool. the command output identifies the problem pool.
Detailed Health Status
You can request a more detailed health summary status by using the -v option. Any pool that is not in the ONLINE state should be investigated for potential problems. you might not have to online the replaced device. the faulted device should be replaced. In the preceding example. For example:
# zpool online tank c1t0d0 Bringing device c1t0d0 online # zpool status -x all pools are healthy
If the autoreplace property is on.

or by using multiported devices such as the devices on a SAN. If any of the file systems fail to unmount. This task can be accomplished by physically recabling the devices. This operation flushes any unwritten data to disk. ZFS enables you to export the pool from one machine and import it on the destination system. If you do not explicitly export the pool. which might reside on different machines. you might lose the last few seconds of data transactions. you might need to move a storage pool between systems. even if the system are of different architectural endianness. By default. use the zpool export command. To do so. the storage devices must be disconnected from the original system and reconnected to the destination system. However. For information about replicating or migrating file systems between different storage pools. and the pool will appear faulted on the original system because the devices are no longer present.
Exporting a ZFS Storage Pool
To export a pool. writes data to the disk indicating that the export was done.
■ ■ ■ ■ ■ ■
“Preparing for ZFS Storage Pool Migration” on page 115 “Exporting a ZFS Storage Pool” on page 115 “Determining Available Storage Pools to Import” on page 116 “Importing ZFS Storage Pools From Alternate Directories” on page 118 “Importing ZFS Storage Pools” on page 118 “Recovering Destroyed ZFS Storage Pools” on page 121
Preparing for ZFS Storage Pool Migration
Storage pools should be explicitly exported to indicate that they are ready to be migrated. you can still import the resulting pool on another system. the destination system cannot import a pool that has not been explicitly exported. For example:
# zpool export tank
The command attempts to unmount any mounted file systems within the pool before continuing. but instead remove the disks manually. see “Sending and Receiving ZFS Data” on page 207.Migrating ZFS Storage Pools
Migrating ZFS Storage Pools
Occasionally. you can forcefully unmount them by using the -f option. For example:
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. This condition is necessary to prevent you from accidentally importing an active pool that consists of network-attached storage that is still in use on another system. and removes all information about the pool from the system.

For more information about ZFS volumes.
Determining Available Storage Pools to Import
After the pool has been removed from the system (either through an explicit export or by forcefully removing the devices). importing a pool that is currently in use by another system over a storage network can result in data corruption and panics as both systems attempt to write to the
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. the devices cannot be identified as cleanly exported. even with the -f option. Each pool is identified by a name as well as a unique numeric identifier. For example:
# zpool import pool: tank id: 11809215114195894163 state: ONLINE action: The pool can be imported using its name or numeric identifier. you can use the numeric identifier to distinguish between them. However. config: tank mirror-0 c1t0d0 c1t1d0 ONLINE ONLINE ONLINE ONLINE
In this example. the devices do not necessarily have to be attached under the same device name. If devices are unavailable at the time of export. the pool cannot be exported. see “ZFS Volumes” on page 253. In addition. first ensure that all consumers of the volume are no longer active. If multiple pools with the same name are available to import. the pool tank is available to be imported on the target system.” If ZFS volumes are in use in the pool. To discover available pools. ZFS detects any moved or renamed devices. the pool tank is no longer visible on the system. you can attach the devices to the target system. Similar to the zpool status command output. but a successful pool migration depends on the overall health of the devices.Migrating ZFS Storage Pools
# zpool export tank cannot unmount ’/export/home/eschrock’: Device busy # zpool export -f tank
After this command is executed. To export a pool with a ZFS volume. and adjusts the configuration appropriately. the user can force the pool to be imported. run the zpool import command with no options. the zpool import output includes a link to a knowledge article with the most up-to-date information regarding repair procedures for the problem that is preventing a pool from being imported. ZFS can handle some situations in which only some of the devices are available. In this case. it appears as “potentially active. If one of these devices is later attached to a system without any of the working devices.

sun. In some cases.Migrating ZFS Storage Pools
same storage.com/msg/ZFS-8000-6X config: raidz1-0 FAULTED c1t0d0 ONLINE c1t1d0 FAULTED c1t2d0 ONLINE c1t3d0 FAULTED
In this example. not enough devices are present to determine the complete configuration. For example:
# zpool import pool: dozer id: 9784486589352144634 state: FAULTED status: One or more devices are missing from the system. Attach the missing devices and try again. If too many faulted or missing devices are present. The pool can be imported despite missing or damaged devices. see: http://www. The fault tolerance of the pool may be compromised if imported. see: http://www.sun. though ZFS does report as much information as possible about the situation.com/msg/ZFS-8000-6X config: dozer FAULTED missing device raidz1-0 ONLINE
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. action: The pool cannot be imported. two disks are missing from a RAID-Z virtual device. For example:
# zpool pool: id: state: status: action: import tank 11809215114195894163 DEGRADED One or more devices are missing from the system. the pool cannot be imported.sun. though you can still import the pool because the mirrored data is still accessible. the first disk is damaged or missing. the pool appears in the DEGRADED state. ZFS cannot determine what other devices were part of the pool. If some devices in the pool are not available but sufficient redundant data exists to provide a usable pool. For example:
# zpool pool: id: state: action: import dozer 9784486589352144634 FAULTED The pool cannot be imported. In this case. Attach the missing devices and try again. see: http://www. which means that sufficient redundant data is not available to reconstruct the pool.com/msg/ZFS-8000-2Q config: NAME tank mirror-0 c1t0d0 c1t3d0 STATE READ WRITE CKSUM DEGRADED 0 0 0 DEGRADED 0 0 0 UNAVAIL 0 0 0 cannot open ONLINE 0 0 0
In this example.

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. or you are using pools backed by files. config: dozer ONLINE mirror-0 ONLINE /file/a ONLINE /file/b ONLINE # zpool import -d /file dozer
If devices exist in multiple directories.Migrating ZFS Storage Pools
c1t0d0 ONLINE c1t1d0 ONLINE c1t2d0 ONLINE c1t3d0 ONLINE Additional devices are known to be part of this pool.
Importing ZFS Storage Pools
After a pool has been identified for import. you can import it by specifying the name of the pool or its numeric identifier as an argument to the zpool import command. For example:
# zpool pool: id: state: action: config: import dozer 2704475622193776801 ONLINE The pool can be imported using its name or numeric identifier. though their exact configuration cannot be determined. the zpool import command only searches devices within the /dev/dsk directory. For example:
# zpool import tank
If multiple available pools have the same name. you must specify which pool to import by using the numeric identifier. For example:
# zpool create dozer mirror /file/a /file/b # zpool export dozer # zpool import -d /file pool: dozer id: 7318163511366751416 state: ONLINE action: The pool can be imported using its name or numeric identifier.
Importing ZFS Storage Pools From Alternate Directories
By default. you must use the -d option to search alternate directories. you can specify multiple -d options. If devices exist in another directory.

different hosts. For example:
# zpool import dozer cannot import ’dozer’: pool may be in use on another system use ’-f’ to import anyway # zpool import -f dozer Note – Do not attempt to import a pool that is active on one system to another system. If the pool was not cleanly exported. For example:
# zpool import dozer zeepool
This command imports the exported pool dozer using the new name zeepool. you can import the pool under a different name. The new pool name is persistent. distributed. For example:
# zpool import dozer The devices below are missing. ZFS requires the -f flag to prevent users from accidentally importing a pool that is still in use on another system. then it will not import. For more information on alternate root pools. or parallel file system and cannot provide concurrent access from multiple.
Importing a Pool With a Missing Log Device
You can import a pool with a missing log device.
Pools can also be imported under an alternate root by using the -R option. ZFS is not a native cluster.
dozer ONLINE c1t8d0 ONLINE # zpool import dozer cannot import ’dozer’: more than one matching pool import by numeric ID instead # zpool import 6223921996155991199
If the pool name conflicts with an existing pool name. If a pool has a missing log device. see “Using ZFS Alternate Root Pools” on page 261.Migrating ZFS Storage Pools
dozer c1t9d0 pool: id: state: action: config:
ONLINE ONLINE
dozer 6223921996155991199 ONLINE The pool can be imported using its name or numeric identifier. use ’-m’ to import the pool anyway: c3t3d0 [log] cannot import ’dozer’: one or more devices is currently unavailable
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.

/dev/dsk/c2t3d0. this feature might allow you to recover the pool's data. the command must include the specific device's slice identifier. in this example. the following conditions apply:
■ ■
All file systems and volumes are mounted in read-only mode. For example:
# zpool import -o readonly=on tank # zpool scrub tank cannot scrub tank: pool is read-only
When a pool is imported in read-only mode.
# zpool import -d /dev/dsk/c2t3d0s0 dpool # zpool status dpool pool: dpool state: ONLINE scan: resilvered 952K in 0h0m with 0 errors on Thu Mar 10 10:28:46 2011 config: NAME dpool mirror-0 c2t3d0 c2t1d0 STATE ONLINE ONLINE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0 0 0 0 0 0 0
An existing limitation is that even though this pool is comprised of whole disks. If a pool is so damaged that it cannot be accessed. For example:
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.
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A read-only pool can be set back to read-write mode by exporting and importing the pool.
Recovering Destroyed ZFS Storage Pools
You can use the zpool import -D command to recover a storage pool that has been destroyed. For example:
# zpool export tank # zpool import tank # zpool scrub tank
Importing a Pool By a Specific Device Path
The following command imports the pool dpool by identifying one of the pool's specific devices. Pool transaction processing is disabled. Attempts to set a pool property during the read-only import are ignored. This also means that any pending synchronous writes in the intent log are not played until the pool is imported read-write.Migrating ZFS Storage Pools
Importing a Pool in Read-Only Mode
You can import a pool in read-only mode.

you can identify the tank pool as the destroyed pool because of the following state information:
state: ONLINE (DESTROYED)
To recover the destroyed pool. action: Attach the missing device and online it using ’zpool online’.sun. For example:
# zpool destroy dozer # zpool import -D pool: dozer id: 13643595538644303788 state: DEGRADED (DESTROYED) status: One or more devices could not be opened. you would import the degraded pool and then attempt to fix the device failure.com/msg/ZFS-8000-2Q config: NAME dozer raidz2-0 c2t8d0
122
STATE READ WRITE CKSUM DEGRADED 0 0 0 DEGRADED 0 0 0 ONLINE 0 0 0
Oracle Solaris ZFS Administration Guide • January 2011
. config: tank mirror-0 c1t0d0 c1t1d0 ONLINE ONLINE ONLINE ONLINE
In this zpool import output. Sufficient replicas exist for the pool to continue functioning in a degraded state. run the zpool import -D command again with the pool to be recovered. For example:
# zpool import -D tank # zpool status tank pool: tank state: ONLINE scrub: none requested config: NAME tank mirror-0 c1t0d0 c1t1d0 STATE ONLINE ONLINE ONLINE ONLINE READ WRITE CKSUM
errors: No known data errors
If one of the devices in the destroyed pool is faulted or unavailable. see: http://www.Migrating ZFS Storage Pools
# zpool destroy tank # zpool import -D pool: tank id: 5154272182900538157 state: ONLINE (DESTROYED) action: The pool can be imported using its name or numeric identifier. you might be able to recover the destroyed pool anyway by including the -f option. In this scenario.

you can run the zpool upgrade command to upgrade all of your pools.Upgrading ZFS Storage Pools
c1t1d0 ONLINE errors: No known data errors
0
0
0
You can use the following syntax to identify additional information about a particular version and supported releases: Then.
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. For example:
# zpool upgrade -a Note – If you upgrade your pool to a later ZFS version. the pool will not be accessible on a system that runs an older ZFS version.

In the Oracle Solaris 11 Express release.solarisinternals.C H A P T E R
Managing ZFS Root Pool Components
5
5
This chapter describes how to manage your Oracle Solaris ZFS root pool components. go to the following site: http://www. cloning a ZFS boot environment.
125
. You can use an AI manifest to determine the disk and the disk partitions to be used for the ZFS root pool.
■
Swap and dump devices are automatically created on ZFS volumes in the ZFS root pool by both of the above installation methods. The following sections are provided in this chapter:
■ ■ ■ ■ ■ ■
“Managing ZFS Root Pool Components (Overview)” on page 125 “Oracle Solaris 11 Express Installation Requirements for ZFS Support” on page 126 “Managing Your ZFS Root Pool” on page 128 “Managing Your ZFS Swap and Dump Devices” on page 131 “Booting From a ZFS Root File System” on page 134 “Recovering the ZFS Root Pool or Root Pool Snapshots” on page 138
For up-to-date troubleshooting information. Oracle Solaris 11 Express Automated Installer (AI) – Automatically installs a ZFS root pool on a SPARC based or x86 based system. such as attaching a root pool mirror. and resizing swap and dump devices. see “Managing Your ZFS Swap and Dump Devices” on page 131.php/ZFS_Troubleshooting_Guide
Managing ZFS Root Pool Components (Overview)
ZFS is the default root file system in the Oracle Solaris 11 Express releases.com/wiki/index. For more information about managing ZFS swap and dump devices. you can install and boot from a ZFS root file system in the following ways:
■
Oracle Solaris 11 Express Live CD – Installs a ZFS root pool on an x86 based system on a single disk. You can use the fdisk partition menu during the installation to partition the disk for your environment.

ZFS Storage Pool Space Requirements
When a system is installed.Managing ZFS Root Pool Components (Overview)
You cannot configure a mirrored root pool during an Oracle Solaris 11 Express installation. the following features are available:
■ ■
Oracle Solaris 11 Express Live CD is available for x86 systems only Oracle Solaris 11 Express provides the Automated Installer features for SPARC based and x86 based systems
General ZFS Storage Pool Requirements
Review the following sections that describe ZFS root pool space and configuration requirements. The space is consumed as follows:
■
■
Swap area and dump device – The default sizes of the swap and dump volumes that are created by the Solaris installation programs are as follows:
■ ■
The default swap volume size is calculated as half the size of physical memory The default dump volume size is calculated by the kernel based on dumpadm information and the size of physical memory
After installation. For more information. The minimum amount of available pool space for a bootable ZFS root file system depends upon the amount of physical memory. Review the following ZFS storage pool space requirements:
■
1 GB of memory is recommended to install a ZFS root file system and for overall better ZFS performance At least 13 GBs of disk space is recommended. the disk space available. you can adjust the sizes of your swap and dump volumes to sizes of your choosing as long as the new sizes support system operation.
Oracle Solaris 11 Express Release Requirements
ZFS is the default root file system for all Oracle Solaris 11 Express releases. see “Adjusting the Sizes of Your ZFS Swap and Dump Devices” on page 132. For more information about configuring a mirrored root pool.
Oracle Solaris 11 Express Installation Requirements for ZFS Support
Review the following Oracle Solaris 11 Express installation requirement sections. and the number of boot environments (BEs) to be created. the size of the swap area and the dump device are dependent upon the amount of physical memory. In addition. see “How to Configure a Mirrored Root Pool” on page 130.
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.

with the exception of /var. see “Creating a ZFS Root Pool” on page 74. Solaris OS Components – All subdirectories of the root file system that are part of the OS image. This requirement should be met if the pool is created with disk slices. Each ZFS BE that is cloned from another ZFS BE doesn't need additional disk space unless it is patched or upgraded.
■
On an x86 based system. If you attempt to use an unsupported pool configuration during an beadm operation. A Solaris fdisk partition is created automatically when the x86 based system is installed. must be in the same dataset as the root file system. 8 GB swap and dump devices are created on a system with 16 GBs of memory. Renaming the root pool might cause an unbootable system. For example. For more information about Solaris fdisk partitions. Consider that BE size will increase when patches are applied or the BE is upgraded. all Solaris OS components must reside in the root pool with the exception of the swap and dump devices.Managing ZFS Root Pool Components (Overview)
■
Boot environment (BE) – A ZFS BE is approximately 4-6 GB. No way exists to enable compression on a root pool during installation. The pool must exist either on a disk slice or on disk slices that are mirrored. Compression can be enabled on the root pool but only after the root pool is installed. In addition. The gzip compression algorithm is not supported on root pools. see “Guidelines for Creating an fdisk Partition” in System Administration Guide: Devices and File Systems. The disk that is intended for the root pool must be less than 2 TBs in size so that the Solaris OS can boot successfully. Do not rename the root pool after it is created by an initial installation. All ZFS BEs in the same root pool use the same swap and dump devices. the disk must contain a Solaris fdisk partition.
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. you will see a message similar to the following:
ERROR: ZFS pool name does not support boot environments
■
■
For a detailed description of supported ZFS root pool configurations.
■
ZFS Storage Pool Configuration Requirements
Review the following ZFS storage pool configuration requirements:
■
The disk that is intended for the root pool must have an SMI label. Swap and dump volumes are determined by the amount of physical memory on the system.

If you do not identify a target disk for the root pool. review your ZFS storage pool and file system information. the installation will fail.5K /rpool 111G 31K legacy 111G 5. After the installation. such as c1t0d0s0. or the physical device path. Otherwise. In addition. Similar to the Oracle Solaris 11 Express Live CD installation method.Managing Your ZFS Root Pool
Managing Your ZFS Root Pool
The following sections provide information about installing and updating a ZFS root pool and configuring a mirrored root pool.9G rpool/ROOT 6. you can only install a root pool onto one disk with the automated installer. With the Oracle Solaris 11 Express automated installation (AI) method. For example:
# zpool pool: state: scrub: config: status rpool ONLINE none requested NAME STATE rpool ONLINE c1t3d0s0 ONLINE READ WRITE CKSUM 0 0 0 0 0 0
errors: No known data errors # zfs list rpool 22. the default target disk is selected as follows:
■ ■ ■ ■
The installer searches for a disk based on a recommended size of approximately 13 GB The disks are searched based on an order determined by the libdiskmgt library The installer selects the first disk that matches the recommended size If no disk matches the recommended size.20G /
Oracle Solaris ZFS Administration Guide • January 2011
. Also keep in mind that the disk intended for the root pool must have an SMI label. the automated installation fails
The AI installer provides the flexibility of installing a ZFS root pool on the default boot disk or on a target disk that you identify.
Installing a ZFS Root Pool
The Oracle Solaris 11 Express Live CD installation method installs a default ZFS root pool on a single disk. you can use the MPxIO identifier or the device ID for the device to be installed.80G
128
111G 76. See the next section for configuring a mirrored root pool. You can specify the logical device. you can create an AI manifest with the <ai_target_device> tag to identify the disk that is used to install the ZFS root pool.80G rpool/ROOT/solaris 6.

see “Oracle Solaris 11 Express Installation Requirements for ZFS Support” on page 126. In most cases. a swap area is created on a ZFS volume in the ZFS root pool.” in System Administration Guide: Common System Management Tasks. “Managing System Crash Information (Tasks).” in System Administration Guide: Devices and File Systems and Chapter 13.
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. then you will need to enable it with the dumpadm command after it is recreated. In general. Consider the following issues when working with ZFS swap and dump devices:
■ ■ ■
Separate ZFS volumes must be used for the swap area and dump devices. If you need to change your swap area or dump device after the system is installed or upgraded. For more information.
Managing Your ZFS Swap and Dump Devices
During the installation process. see Chapter 21. a dump device is created on a ZFS volume in the ZFS root pool. see “Adjusting the Sizes of Your ZFS Swap and Dump Devices” on page 132. Currently. you will only have to adjust the size of the dump device by using the zfs command. either by using the eeprom command. For more information. “Configuring Additional Swap Space (Tasks). the setenv command from the SPARC boot PROM. For example:
# dumpadm Dump content: Dump device: Savecore directory: Savecore enabled: Save compressed: kernel pages /dev/zvol/dsk/rpool/dump (dedicated) /var/crash/t5120 yes on
If you disable and remove the dump device. or reconfigure the PC BIOS. use the swap and dumpadm commands as in previous Solaris releases. Both the swap volume size and the dump volume size can be adjusted after installation.Managing Your ZFS Swap and Dump Devices
4 5
Verify that you can boot successfully from the second disk. a dump device requires no administration because it is setup automatically at installation time. For information about the swap and dump volume sizes that are created by the installation programs. Set up the system to boot automatically from the new disk.2 swaplo blocks free 16 16646128 16646128
During the installation process. For example:
# swap -l swapfile dev /dev/zvol/dsk/rpool/swap 145. using a swap file on a ZFS file system is not supported.

# zfs create -V 2G -b 4k rpool/swap
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You must enable the swap area when a new swap device is added or changed.
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.3 16 4194288 4194288
Add an entry for the second swap volume to the /etc/vfstab file.
■
Select one of the following if you need to recreate your swap area:
■
On a SPARC based system. For example:
# swap -d /dev/zvol/dsk/rpool/swap # zfs volsize=2G rpool/swap # swap -a /dev/zvol/dsk/rpool/swap
For information on removing a swap device on an active system. see this site: http://www. Add an entry for the swap volume to the /etc/vfstab file. Then. create your swap area.solarisinternals.1 16 1058800 1058800 /dev/zvol/dsk/rpool/swap2 256. Set the block size to 8 KB. just add another swap volume. Set the block size to 4 KB. activate the new swap volume.
■ ■
Adjust the size of your swap and dump volumes. create your swap area. You can reset the volsize property of the dump device after a system is installed. it is best to remove the swap device first. For example:
# zfs set volsize=2G rpool/dump # zfs get volsize rpool/dump NAME PROPERTY VALUE rpool/dump volsize 2G
SOURCE -
■
You can resize the swap volume but until CR 6765386 is integrated. For example:
# zfs create -V 2G rpool/swap2
Then. recreate the swap and dump volumes.
# zfs create -V 2G -b 8k rpool/swap
■
On an x86 based system.com/wiki/index. recreate it.Managing Your ZFS Swap and Dump Devices
Adjusting the Sizes of Your ZFS Swap and Dump Devices
You might need to adjust the size of swap and dump devices after installation or possibly. For example:
# swap -a /dev/zvol/dsk/rpool/swap2 # swap -l swapfile dev swaplo blocks free /dev/zvol/dsk/rpool/swap 256.php/ZFS_Troubleshooting_Guide
■
If you need more swap space on a system that is already installed.

If. see “Planning for Swap Space” in System Administration Guide: Devices and File Systems. a message similar to the following is displayed:
# dumpadm -d /dev/zvol/dsk/rpool/dump dumpadm: dump device /dev/zvol/dsk/rpool/dump is too small to hold a system dump dump size 36255432704 bytes. use syntax similar to the following:
# dumpadm -d /dev/zvol/dsk/rpool/dump Dump content: kernel pages Dump device: /dev/zvol/dsk/rpool/dump (dedicated) Savecore directory: /var/crash/t5120 Savecore enabled: yes Save compressed: on
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A system with 128 GB or greater memory will need a larger dump device than the dump device that is created by default. device size 34359738368 bytes
For information on sizing the swap and dump devices. on a large-memory system. for any reason. you need to enable a dump device after you create a dump device manually. In most cases. the dump device size is increased to 40 GB as follows:
# zfs set volsize=40G rpool/dump
■
Resizing a large dump device can be a time-consuming process.
■
If a crash dump was not created automatically.
■
You cannot currently add a dump device to a pool with multiple top level-devices. you will only need to adjust the size of the dump device if the default dump device size is too small. For example.Managing Your ZFS Swap and Dump Devices
Troubleshooting ZFS Dump Device Issues
Review the following items if you have problems either capturing a system crash dump or resizing the dump device. you can use the savecore command to save the crash dump. A dump device is created automatically when you initially install a ZFS root file system or migrate to a ZFS root file system. If the dump device is too small to capture an existing crash dump. You will see a message similar to the following:
# dumpadm -d /dev/zvol/dsk/datapool/dump dump is not supported on device ’/dev/zvol/dsk/datapool/dump’: ’datapool’ has multiple top level vdevs
Add the dump device to the root pool. which cannot have multiple top-level devices.
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.

the dataset selected for booting is the one identified by the pool's bootfs property. When booting from a ZFS root file system. For more information about creating a mirrored root pool. you must specify a boot device and a root file system within the pool that was identified by the boot device.Booting From a ZFS Root File System
Booting From a ZFS Root File System
Both SPARC based and x86 based systems boot with a boot archive. you might need to update the PROM or the BIOS to specify a different boot device.
# zpool pool: state: scrub: config: status rpool ONLINE none requested
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. This default selection can be overridden by specifying an alternate bootable dataset that is included in the boot -Z command on a SPARC system or by selecting an alternate boot device from the BIOS on an x86 based system. For example. which is a file system image that contains the files required for booting. By default. If you create a mirrored ZFS root pool with the initial installation method or if you use the zpool attach command to attach a disk to the root pool. you can boot from either disk (c1t0d0s0 or c1t1d0s0) in this pool. not a single root file system. A storage pool can contain multiple bootable ZFS root file systems. The installboot or installgrub command is as follows:
x86# installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c0t1d0s0
sparc# installboot -F zfs /usr/platform/‘uname -i‘/lib/fs/zfs/bootblk /dev/rdsk/c0t1d0s0
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You can boot from different devices in a mirrored ZFS root pool. When booting from ZFS.
Booting From an Alternate Disk in a Mirrored ZFS Root Pool
You can attach a disk to create a mirrored ZFS root pool after installation. the path names of both the boot archive and the kernel file are resolved in the root file system that is selected for booting. a device specifier identifies a storage pool. Depending on the hardware configuration. you must install the boot information on the newly replaced disk by using the installboot or installgrub commands. Booting from a ZFS file system differs from booting from a UFS file system because with ZFS. see “How to Configure a Mirrored Root Pool” on page 130. Review the following known issues regarding mirrored ZFS root pools:
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If you replace a root pool disk by using the zpool replace command. then this step is unnecessary.

In this way.sas@2/disk@1. the menu.lst entry can contain a bootfs command. On a SPARC based system. confirm the active boot device.lst file can contain entries for multiple root file systems within the pool. the menu.25f8@4/pci108e. use syntax similar to the following:
x86# prtconf -v|sed -n ’/bootpath/.286@0/disk@0. By default. an entry similar to the following is added to the menu.2/LSILogic.
ok boot /pci@7c0/pci@0/pci@1/pci@0. Multiple bootable datasets can exist within a pool.0:a’
■
On an x86 based system./value/p’ name=’bootpath’ type=string items=1 value=’/pci@0. However. During an installation and beadm activation process. select an alternate disk in the mirrored ZFS root pool from the appropriate BIOS menu. the bootable dataset entry in the /pool-name/boot/menu.2/LSILogic. the ZFS root file system is automatically designated with the bootfs property. enter the alternate disk at the ok prompt.0/pci8086. two boot options are available:
Chapter 5 • Managing ZFS Root Pool Components 135
.sas@2/disk@1
After the system is rebooted.
Booting From a ZFS Root File System on a SPARC Based System
On a SPARC based system with multiple ZFS BEs.0:a’
On an x86 based system. which specifies an alternate dataset in the pool. you can boot from any BE by using the beadm activate command.Booting From a ZFS Root File System
NAME rpool mirror-0 c1t0d0s0 c1t1d0s0
STATE ONLINE ONLINE ONLINE ONLINE
READ WRITE CKSUM 0 0 0 0 0 0 0 0 0 0 0 0
On a SPARC based system. When a system is installed with a ZFS root file system.lst file is updated automatically.lst file:
title solaris bootfs rpool/ROOT/solaris title solaris-1 bootfs rpool/ROOT/solaris-1
When a new BE is created.lst file is identified by the pool's bootfs property. a menu. For example:
SPARC# prtconf -vp | grep bootpath bootpath: ’/pci@7c0/pci@0/pci@1/pci@0.

you can use the beadm activate command to specify a default BE. you can use the boot -L command.18M 8.lst file during the installation process or beadm activate operation to boot ZFS automatically:
title Oracle Solaris 11 Express snv_152 findroot (pool_rpool.2 ]: 2 To boot the selected entry.
Booting From a Specific ZFS Boot Environment
■
EXAMPLE 5–1
If you have multiple ZFS BEs in a ZFS storage pool on your system's boot device. you can use the boot -L command to display a list of bootable datasets within a ZFS pool.Booting From a ZFS Root File System
■
After a ZFS BE is activated.0:a File and args: -L 1 solaris 2 solaris-1 Select environment to boot: [ 1 .
136 Oracle Solaris ZFS Administration Guide • January 2011
. Then. Detailed instructions for booting that dataset are displayed.lst file is used to create the GRUB menu. the menu. You can boot the selected dataset by following the instructions. For example. you can select one of the bootable datasets in the list.48G Policy -----static static Created ------2011-01-13 15:31 2011-01-13 15:44
If you have multiple ZFS BEs on your SPARC based system. For example:
ok boot -L Boot device: /pci@0/pci@0/pci@2/scsi@0/disk@3. invoke: boot [<root-device>] -Z rpool/ROOT/solaris-1 Program terminated ok boot -Z rpool/ROOT/solaris-1
Booting From a ZFS Root File System on an x86 Based System
The following entries are added to the /pool-name/boot/grub/menu. Use the boot -Z dataset command to boot a specific ZFS dataset. the following ZFS BEs are available as described by the beadm output:
# beadm list BE Active ------solaris solaris-1 NR Mountpoint ---------/ Space ----19.0.a) bootfs rpool/ROOT/solaris kernel$ /platform/i86pc/kernel/$ISADIR/unix -B $ZFS-BOOTFS module$ /platform/i86pc/$ISADIR/boot_archive
If the device identified by GRUB as the boot device contains a ZFS storage pool.

For example:
title Oracle Solaris 11 Express snv_152 findroot (pool_rpool.a) bootfs rpool/ROOT/solaris kernel$ /platform/i86pc/kernel/$ISADIR/unix -B $ZFS-BOOTFS module$ /platform/i86pc/$ISADIR/boot_archive
EXAMPLE 5–3
x86: Fast Rebooting a ZFS Root File System
The fast reboot feature provides the ability to reboot within seconds on x86 based systems. the following option is added. You must still use the init 6 command when transitioning between BEs with the beadm activate command.
-B $ZFS-BOOTFS
EXAMPLE 5–2
x86: Booting a ZFS File System
When booting from a ZFS file system. Follow these steps if your system won't boot because of a problem with the BE contents. you can select a BE from the GRUB menu.
Chapter 5 • Managing ZFS Root Pool Components 137
.Booting From a ZFS Root File System
On an x86 based system with multiple ZFS BEs. you can use the reboot -f command. For other system operations where the reboot command is appropriate.0. the root device is specified by the boot -B $ZFS-BOOTFS parameter. you can reboot to a new kernel without experiencing the long delays that can be imposed by the BIOS and boot loader.
1
Boot from the Oracle Solaris 11 Express Live CD or from an Oracle Solaris 11 Express AI server. The ability to fast reboot a system drastically reduces down time and improves efficiency. see “Recovering the ZFS Root Pool or Root Pool Snapshots” on page 138.
▼ How to Boot ZFS for Recovery Purposes
Keep multiple boot environments to prevent a system boot failure. For example:
# reboot -f
Booting For Recovery Purposes in a ZFS Root Environment
Use the following procedure if you need to boot the system so that you can recover from a lost root password or similar problem. If the root file system corresponding to this menu entry is a ZFS dataset. With the fast reboot feature. If you need to recover a root pool or root pool snapshot.

import the root pool.
# TERM=vt100 # export TERM
6
Update the boot archive
# bootadm update-archive -R /a
7
Reboot the system.lst title solaris bootfs rpool/ROOT/solaris title solaris-1 bootfs rpool/ROOT/solaris-1
If a password or shadow entry is preventing a console login.
# cd /a/etc # vi passwd 5
If necessary. review the menu.
# zpool import rpool
3
Mount the ZFS BE on /a
# beadm mount solaris-1 /a
4
Modify the BE contents to resolve the boot failure.Recovering the ZFS Root Pool or Root Pool Snapshots
2
At the terminal prompt. For example.
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. set the TERM type.
# cat /a/rpool/boot/menu. if the disk is failing so that the system won't boot. before you replace the root pool disk. then correct that problem.lst file to determine if the boot entries are correct. In a non-redundant pool. such as a CD or the network. you'll need to boot from an alternate media.
# init 6
Recovering the ZFS Root Pool or Root Pool Snapshots
The following sections describe how to perform the following tasks:
■ ■ ■
“How to Replace a Disk in the ZFS Root Pool” on page 138 “ How to Create Root Pool Snapshots” on page 140 “ How to Recreate a ZFS Root Pool and Restore Root Pool Snapshots” on page 142
▼
How to Replace a Disk in the ZFS Root Pool
You might need to replace a disk in the root pool for the following reasons:
■ ■
The root pool is too small and you want to replace it with a larger disk The root pool disk is failing.

if the replacement disk fails.php/ZFS_Troubleshooting_Guide
3
Attach the new disk to the root pool. the current root pool disk (c1t10d0s0) is:
/pci@8. you can use the zpool attach command. For example:
# zpool offline rpool c1t0d0s0 # cfgadm -c unconfigure c1::dsk/c1t0d0 <Physically remove failed disk c1t0d0> <Physically insert replacement disk c1t0d0> # cfgadm -c configure c1::dsk/c1t0d0 <Confirm that the new disk has an SMI label and a slice 0> # zpool replace rpool c1t0d0s0 # zpool online rpool c1t0d0s0 # zpool status rpool <Let disk resilver before installing the boot blocks> SPARC# installboot -F zfs /usr/platform/‘uname -i‘/lib/fs/zfs/bootblk /dev/rdsk/c1t0d0s0 x86# installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c1t9d0s0
On some hardware. See the steps below for an example of attaching an additional disk and detaching a root pool disk. For information about relabeling a disk that is intended for the root pool.0 1 2
Physically connect the replacement disk. In the example below.Recovering the ZFS Root Pool or Root Pool Snapshots
In a mirrored root pool configuration. you might be able to attempt a disk replacement without having to boot from alternate media.solarisinternals. You can replace a failed disk by using the zpool replace command or if you have an additional disk.700000/pci@3/scsi@5/sd@9. the replacement boot disk is (c1t9d0s0):
/pci@8. if necessary. you do not have to online or reconfigure the replacement disk after it is inserted. see the following site: http://www. For example:
# zpool attach rpool c1t10d0s0 c1t9d0s0 Make sure to wait until resilver is done before rebooting. Identify the boot device pathnames of the current and new disk so that you can test booting from the replacement disk and also manually boot from the existing disk. Confirm that the replacement (new) disk has an SMI label and a slice 0.700000/pci@3/scsi@5/sd@a.com/wiki/index.
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. Some hardware requires that you offline and unconfigure a disk before attempting the zpool replace operation to replace a failed disk.0
In the example below.

You can also store root pool snapshots as the actual snapshots in a pool on a remote system. the remote dataset can be mounted by using NFS and the snapshot file received into the recreated pool. Sending and receiving the snapshots from a remote system is a bit more complicated because you must configure ssh or use rsh while the system to be repaired is booted from the Solaris OS miniroot. For information about remotely storing and recovering root pool snapshots and the most up-to-date information about root pool recovery.18% done config: NAME rpool mirror-0 c1t3d0s0 c1t2d0s0 STATE ONLINE ONLINE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0 0 0 0 0 0 0 (resilvering)
errors: No known data errors 5
Verify that you can boot from the new disk after resilvering is complete. The pool will continue to function. The best way to create root pool snapshots is to do a recursive snapshot of the root pool. on a SPARC based system:
ok boot /pci@8. For example:
# zpool detach rpool c1t10d0s0
7
Set up the system to boot automatically from the new disk. the setenv command from the SPARC boot PROM. For example:
# zpool status rpool state: ONLINE status: One or more devices is currently being resilvered.php/ZFS_Troubleshooting_Guide
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.0
6
If the system boots from the new disk. 5.
▼
How to Create Root Pool Snapshots
Create root pool snapshots for recovery purposes. detach the old disk.com/wiki/index.3G at 16. In the case of a root pool failure. 0h15m to go 813M resilvered. either by using the eeprom command. or reconfigure the PC BIOS. action: Wait for the resilver to complete. possibly in a degraded state. scan: resilver in progress since Fri Jan 14 13:35:45 2011 814M scanned out of 15. The procedure below creates a recursive root pool snapshot and stores the snapshot as a file in a pool on a remote system.Recovering the ZFS Root Pool or Root Pool Snapshots
4
Confirm the root pool status.solarisinternals. go to this site: http://www. For example.3M/s.700000/pci@3/scsi@5/sd@9.

you'll need to exit the installation program. select one of the following boot methods:
ok boot net -s ok boot cdrom -s
If you don't use -s option. you might need to specify the remote-system's IP address. For more information about relabeling the disk. Then.Recovering the ZFS Root Pool or Root Pool Snapshots
sending sending sending sending sending sending
from from from from from from
@osolBE to rpool/ROOT/osolBE@0311 @ to rpool/ROOT/opensolaris@0311 @ to rpool/swap@0311 @ to rpool/export@0311 @ to rpool/export/home@0311 @ to rpool/export/home/admin@0311
▼
How to Recreate a ZFS Root Pool and Restore Root Pool Snapshots
In this scenario.php/ZFS_Troubleshooting_Guide
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. On a SPARC based system.
3
If the root pool disk is replaced and does not contain a disk label that is usable by ZFS.solarisinternals. you will need to add the -o version=version-number property option and value when you recreate the root pool in step 4 below. On an x86 based system. Otherwise.
2
Mount the remote snapshot dataset. go to the following site: http://www. For example:
# mount -F nfs remote-system:/rpool/snaps /mnt
If your network services are not configured.
All steps below are performed on the local system. select the option for booting from the DVD or the network.
1
Boot from CD/DVD or the network.com/wiki/index. exit the installation program. assume the following conditions:
■ ■ ■
ZFS root pool cannot be recovered ZFS root pool snapshots are stored on a remote system and are shared over NFS The system is booted from an equivalent Solaris release to the root pool version so that the Solaris release and the pool version match. you will have to relabel the disk.

but these features are only covered briefly in this chapter. and clones are also managed by using this command. The following sections are provided in this chapter:
■ ■ ■ ■ ■ ■ ■ ■ ■
“Managing ZFS File Systems (Overview)” on page 145 “Creating. Destroying. Concepts such as the hierarchical file system layout.C H A P T E R
Managing Oracle Solaris ZFS File Systems
6
6
This chapter provides detailed information about managing Oracle Solaris ZFS file systems. and Renaming ZFS File Systems” on page 146 “Introducing ZFS Properties” on page 149 “Querying ZFS File System Information” on page 166 “Managing ZFS Properties” on page 169 “Mounting and Sharing ZFS File Systems” on page 173 “Setting ZFS Quotas and Reservations” on page 181 “Encrypting ZFS File Systems” on page 187 “Upgrading ZFS File Systems” on page 192
Managing ZFS File Systems (Overview)
A ZFS file system is built on top of a storage pool. The zfs command provides a set of subcommands that perform specific operations on file systems. ZFS file systems are administered by using the zfs command.” For detailed information about ZFS volumes. Snapshots. Because file systems are so lightweight and because they are the central point of administration in ZFS. This chapter describes these subcommands in detail. “Working With Oracle Solaris ZFS Snapshots and Clones. you are likely to create many of them.
145
. property inheritance. volumes. File systems can be dynamically created and destroyed without requiring you to allocate or format any underlying disk space. For detailed information about snapshots and clones. see “ZFS Volumes” on page 253. see Chapter 7. and automatic mount point management and share interactions are included.

a mount point of /export/zfs is created for the tank/home file system:
146 Oracle Solaris ZFS Administration Guide • January 2011
. For information about encrypting a ZFS file system. In the following example. The file system name is specified as a path name starting from the name of the pool as follows: pool-name/[filesystem-name/]filesystem-name The pool name and initial file system names in the path identify the location in the hierarchy where the new file system will be created.
# zfs create tank/home/bonwick
ZFS automatically mounts the newly created file system if it is created successfully. a file system named bonwick is created in the tank/home file system. see zfs(1M). Encrypting a ZFS file system must be enabled when the file system is created. see “Managing ZFS Mount Points” on page 174.Creating. and Renaming ZFS File Systems
Note – The term dataset is used in this chapter as a generic term to refer to a file system. The file system name must satisfy the naming requirements in “ZFS Component Naming Requirements” on page 55. ZFS file systems can be renamed by using the zfs rename command. file systems are mounted as /dataset. In the following example. Destroying. see “Encrypting ZFS File Systems” on page 187. Destroying. the newly created bonwick file system is mounted at /tank/home/bonwick. By default. The last name in the path identifies the name of the file system to be created. clone. For more information about the zfs create command. using the path provided for the file system name in the create subcommand. or volume. and Renaming ZFS File Systems
ZFS file systems can be created and destroyed by using the zfs create and zfs destroy commands. In this example.
Creating. For more information about automatically managed mount points. The create subcommand takes a single argument: the name of the file system to be created. snapshot.
■ ■ ■
“Creating a ZFS File System” on page 146 “Destroying a ZFS File System” on page 147 “Renaming a ZFS File System” on page 148
Creating a ZFS File System
ZFS file systems are created by using the zfs create command. You can set file system properties when the file system is created.

If the file system to be destroyed is busy and cannot be unmounted. including cloned file systems outside the target hierarchy. To force the destruction of all dependents. the -R option must be used. For more information about automatically managed mounts or automatically managed shares.
# zfs destroy tank/home/ahrens cannot unmount ’tank/home/ahrens’: Device busy # zfs destroy -f tank/home/ahrens
The zfs destroy command also fails if a file system has descendents. causing unexpected application behavior. Use it with extreme
caution. Use this option with caution as it can unmount. so use this option with caution. To recursively destroy a file system and all its descendents. use the zfs destroy command. unshare. use the -r option. use the -f option. and destroy active file systems. In the following example.
# zfs destroy tank/ws cannot destroy ’tank/ws’: filesystem has children use ’-r’ to destroy the following datasets: tank/ws/billm tank/ws/bonwick tank/ws/maybee # zfs destroy -r tank/ws
If the file system to be destroyed has indirect dependents.
Destroying a ZFS File System
To destroy a ZFS file system. Note that a recursive destroy also destroys snapshots. even the recursive destroy command fails.
# zfs destroy -r tank/home/schrock cannot destroy ’tank/home/schrock’: filesystem has dependent clones use ’-R’ to destroy the following datasets:
Chapter 6 • Managing Oracle Solaris ZFS File Systems 147
. Use extreme caution with this option. see “Introducing ZFS Properties” on page 149. The destroyed file system is automatically unmounted and unshared. the tabriz file system is destroyed:
# zfs destroy tank/home/tabriz Caution – No confirmation prompt appears with the destroy subcommand. and Renaming ZFS File Systems
# zfs create -o mountpoint=/export/zfs tank/home
For more information about file system properties. Destroying. To destroy an active file system.Creating. the zfs destroy command fails. see “Automatic Mount Points” on page 174.

the new location must be within the same pool and it must have enough disk space to hold this new file system. For more information about quotas. If this problem occurs. -r. see “Setting ZFS Quotas and Reservations” on page 181. Destroying.
For more information about snapshots and clones. Change the name of a file system and relocate it within the ZFS hierarchy. If the new location does not have enough disk space. The rename operation attempts an unmount/remount sequence for the file system and any descendent file systems.
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. For information about renaming snapshots. Relocate the file system within the ZFS hierarchy. see “Renaming ZFS Snapshots” on page 198.Creating. When you relocate a file system through rename. With the rename subcommand. or -R options to the zfs destroy command. The rename command fails if the operation is unable to unmount an active file system. you must forcibly unmount the file system.
The following example uses the rename subcommand to rename of a file system from kustarz to kustarz_old:
# zfs rename tank/home/kustarz tank/home/kustarz_old
The following example shows how to use zfs rename to relocate a file system:
# zfs rename tank/home/maybee tank/ws/maybee
In this example. so use these options carefully. see Chapter 7.”
Renaming a ZFS File System
File systems can be renamed by using the zfs rename command. you can perform the following operations:
■ ■ ■
Change the name of a file system. and Renaming ZFS File Systems
tank/clones/schrock-clone # zfs destroy -R tank/home/schrock Caution – No confirmation prompt appears with the -f. possibly because it has reached its quota. the maybee file system is relocated from tank/home to tank/ws. “Working With Oracle Solaris ZFS Snapshots and Clones. rename operation fails.

Indicates that the property was inherited from the named ancestor. This source is a result of no ancestor having the property set as source local.
■ ■ ■
“ZFS Read-Only Native Properties” on page 159 “Settable ZFS Native Properties” on page 160 “ZFS User Properties” on page 165
Properties are divided into two types. Indicates that the property value was not inherited or set locally. For a description of these values. and clones. All other native properties listed in this table are settable. is propagated down to all of its descendents.Introducing ZFS Properties
Introducing ZFS Properties
Properties are the main mechanism that you use to control the behavior of file systems. native properties and user-defined properties. The source of a property can have the following values: local Indicates that the property was explicitly set on the dataset by using the zfs set command as described in “Setting ZFS Properties” on page 169. the properties defined in this section apply to all the dataset types. In addition.
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. secure. The values are discard. noallow. see “ZFS User Properties” on page 165. Unless stated otherwise. but you can use them to annotate datasets in a way that is meaningful in your environment. Most settable properties are also inheritable. An inheritable property is a property that. Read-only native properties are identified as such. and passthrough. User properties have no effect on ZFS file system behavior. volumes. when set on a parent dataset. For information about user properties. see “ZFS User Properties” on page 165. see “ACL Property (aclinherit)” on page 221. snapshots. Native properties either export internal statistics or control ZFS file system behavior.
inherited from dataset-name default
The following table identifies both read-only and settable native ZFS file system properties. native properties are either settable or read-only.
TABLE 6–1
ZFS Native Property Descriptions
Type Default Value Description
Property Name
aclinherit
String
secure
Controls how ACL entries are inherited when files and directories are created. For more information about user properties. All inheritable properties have an associated source that indicates how a property was obtained.

available
Number
N/A
canmount
Boolean
on
Controls whether a file system can be mounted with the zfs mount command. The property abbreviation is avail. and other datasets within the pool. a mount point can be inherited to descendent file systems. a dataset can only be mounted and unmounted explicitly. nor is it mounted by the zfs mount-a command or unmounted by the zfs unmount-a command. Turning this property off avoids producing write traffic when reading files and can result in significant performance gains. quotas. assuming no other activity in the pool. This property can be set on any file system. The dataset is not mounted automatically when the dataset is created or imported. when this property is set to off. reservations. Read-only property that identifies the amount of disk space available to a dataset and all its children. though it might confuse mailers and similar utilities. see “The canmount Property” on page 162. However. available space can be limited by various factors including physical pool size. For more information. see “ZFS Disk Space Accounting” on page 64. For more information about disk space accounting. but the file system itself is never mounted.
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. When the noauto option is set.Introducing ZFS Properties
TABLE 6–1
ZFS Native Property Descriptions
Type Default Value
(Continued)
Description
Property Name
atime
Boolean
on
Controls whether the access time for files is updated when they are read. Because disk space is shared within a pool. and the property itself is not inheritable.

The values are on. off. lzjb. Currently. The mixed value for this property indicates the file system can support requests for both case-sensitive and case-insensitive matching behavior. A value of off disables integrity checking on user data. gzip. It includes explicit savings through the use of the compression property. Enabling compression on a file system with existing data only compresses new data. For more information about using the mixed value. Enables or disables compression for a dataset. or gzip-N has the same effect as setting this property to on.Introducing ZFS Properties
TABLE 6–1
ZFS Native Property Descriptions
Type Default Value
(Continued)
Description
Property Name
casesensitivity
String
mixed
This property indicates whether the file name matching algorithm used by the file system should be casesensitive. currently fletcher4.
checksum
String
on
Controls the checksum used to verify data integrity. fletcher4. the file system preserves the case of the name specified to create a file. see “The casesensitivity Property” on page 162. expressed as a multiplier. This property cannot be changed after the file system is created. setting this property to lzjb. fletcher2. gzip. Traditionally. The values are on. sha256. and sha256+mac.
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. The default value is on. caseinsensitive. UNIX and POSIX file systems have case-sensitive file names. A value of off is not recommended. off. or allow a combination of both styles of matching (mixed). The value is calculated from the logical size of all files and the amount of referenced physical data. case-insensitive matching behavior on a file system that supports mixed behavior is limited to the Oracle Solaris SMB server product. Regardless of the casesensitivity property setting. Existing data remains uncompressed. and gzip-N. Currently. The property abbreviation is compress. which automatically selects an appropriate algorithm. Compression can be enabled by the zfs set compression=on dataset command.
compression
String
off
compressratio
Number
N/A
Read-only property that identifies the compression ratio achieved for a dataset.

see “The dedup Property” on page 163. 2.Introducing ZFS Properties
TABLE 6–1
ZFS Native Property Descriptions
Type Default Value
(Continued)
Description
Property Name
copies
Number
1
Sets the number of copies of user data per file system. These copies are in addition to any pool-level redundancy. mmap(2) calls with PROT_EXEC are disallowed. and sha256[. and counts against quotas and reservations. when set to off. The availability of a dataset's key is indicated by available or unavailable. Read-only property that identifies the dataset's encryption key status. Possible values are on. Controls the ability to remove duplicate data in a ZFS file system. An encrypted dataset means that data is encoded and a key is needed by the dataset owner to access the data. Controls whether a dataset is encrypted. For more information. The key must be present when the dataset is created.verify].
creation
String String
N/A off
dedup
devices encryption
Boolean Boolen
on off
Controls whether device files in a file system can be opened. passphrase. If encryption is enabled for a new dataset.. or 3. For datasets that do not have encryption enabled. The default checksum for deduplication is sha256. Available values are 1. verify. hex. or loaded by using the zfs key -l command. Controls whether programs in a file system are allowed to be executed. Read-only property that identifies the date and time that a dataset was created. the used property is updated when multiple copies are enabled. the default keysource is passphrase.prompt. none is displayed. The valid property values are raw.
exec
Boolean
on
keysource
String
none
keystatus
String
none
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. mounted. off. or file.prompt. In addition. Consider setting this property when the file system is created because changing this property on an existing file system only affects newly written data. Disk space used by multiple copies of user data is charged to the corresponding file and dataset. Also. Identifies the format and location of the key that wraps the dataset keys.

If the labeled dataset matches the labeled zone. clone. For more information about using this property. ZFS uses the pool's separate log devices. to handle the requests at low latency. see “Managing ZFS Mount Points” on page 174. the file system and any descendents that inherit the mount point are unmounted. or if they were mounted before the property was changed. they are automatically remounted in the new location if the property was previously legacy or none. then they remain unmounted. If the new value is legacy. This property can only be modified when Trusted Extensions is enabled and only with the appropriate privilege. When the mountpoint property is changed for a file system. If logbias is set to throughput. the dataset can be mounted and accessed from the labeled zone. or snapshot is currently mounted. If set to none.
nbmand
Boolean
off
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. Controls the mount point used for this file system. Provides a sensitivity label that determines if a dataset can be mounted in a Trusted Extensions zone. If set to all. The default value is none. Otherwise. neither user data nor metadata is cached.Introducing ZFS Properties
TABLE 6–1
ZFS Native Property Descriptions
Type Default Value
(Continued)
Description
Property Name
logbias
String
latency
Controls how ZFS optimizes synchronous requests for this dataset. If set to metadata. any shared file systems are unshared and shared in the new location. and metadata. Instead.
mlslabel
String
None
mounted
Boolean
N/A
mountpoint
String
N/A
primarycache
String
all
Controls what is cached in the primary cache (ARC). The value can be either yes or no. In addition. This property is for SMB clients only. none. ZFS optimizes synchronous operations for global pool throughput and efficient use of resources. If logbias is set to latency. Changes to this property only take effect when the file system is unmounted and remounted. both user data and metadata are cached. only metadata is cached. Read-only property that indicates whether a file system. This property does not apply to volumes. ZFS does not use the pool's separate log devices. Controls whether the file system should be mounted with nbmand (Non-blocking mandatory) locks. The default value is latency. if any. Possible values are all.

The property abbreviation is rdonly. The origin cannot be destroyed (even with the -r or -f option) as long as a clone exists.
rekeydate
String
N/A
Read-only property that indicates the date of the last data encryption key change from a zfs key -K or zfs clone -K operation on this dataset. Controls whether a dataset can be modified. the utf8only property is automatically set to on. such as file systems and snapshots. This property cannot be changed after the file system is created. Setting a quota on a descendent of a dataset that already has a quota does not override the ancestor's quota. If this property is set to a legal value other than none. but rather imposes an additional limit. For information about setting quotas. and which normalization algorithm should be used. see “Setting Quotas on ZFS File Systems” on page 182. Quotas cannot be set on volumes. no modifications can be made. When set to on. If no rekey operation has been performed. This property enforces a hard limit on the amount of disk space used. and the utf8only property was left unspecified. The property abbreviation is recsize.
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. see “The recordsize Property” on page 164. the value of this property is the same as the creation date. names are normalized as part of any comparison process. as the volsize property acts as an implicit quota. including all space consumed by descendents. Read-only property for cloned file systems or volumes that identifies the snapshot from which the clone was created. For a detailed description. File names are always stored unmodified. The default value of the normalization property is none.Introducing ZFS Properties
TABLE 6–1
ZFS Native Property Descriptions
Type Default Value
(Continued)
Description
Property Name
normalization
String
None
This property indicates whether a file system should perform a unicode normalization of file names whenever two file names are compared. Non-cloned file systems have an origin of none.
origin
String
N/A
quota
Number (or none none)
Limits the amount of disk space a dataset and its descendents can consume.
readonly
Boolean
off
recordsize
Number
128K
Specifies a suggested block size for files in a file system.

it initially references the same amount of disk space as the file system or snapshot it was created from. such as snapshots and clones. Sets the minimum amount of disk space that is guaranteed to a dataset. When a snapshot or clone is created. a snapshot is only allowed if enough free pool space is available outside of this reservation to accommodate the current number of referenced bytes in the dataset. For more information. see “Setting Reservations on ZFS File Systems” on page 185. such as snapshots and clones. the dataset is treated as if it were taking up the amount of space specified by refreservation.
refreservation
Number (or none none)
reservation
Number (or none none)
Sets the minimum amount of disk space guaranteed to a dataset and its descendents. The property abbreviation is reserv.
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. and count against the parent dataset's quotas and reservations. This hard limit does not include disk space used by descendents. The property abbreviation is refer. The property abbreviation is refreserv.Introducing ZFS Properties
TABLE 6–1
ZFS Native Property Descriptions
Type Default Value
(Continued)
Description
Property Name
referenced
Number
N/A
Read-only property that identifies the amount of data accessible by a dataset.
refquota
Number (or none none)
Sets the amount of disk space that a dataset can consume. which might or might not be shared with other datasets in the pool. If refreservation is set. Reservations are accounted for in the parent dataset's disk space used. and counts against the parent dataset's quotas and reservations. because its contents are identical. When the amount of disk space used is below this value. When the amount of disk space used is below this value. not including descendents. the dataset is treated as if it were using the amount of space specified by its reservation. The refreservation reservation is accounted for in the parent dataset's disk space used. This property enforces a hard limit on the amount of space used.

Otherwise. When rstchown is set to off. For more information about sharing ZFS file systems. the user has the PRIV_FILE_CHOWN_SELF privilege for chown operations.Introducing ZFS Properties
TABLE 6–1
ZFS Native Property Descriptions
Type Default Value
(Continued)
Description
Property Name
rstchown
Boolean
on
Indicates whether the file system owner can grant file ownership changes. only metadata is cached. and metadata.
secondarycache
String
all
setuid
Boolean String
on
sharenfs
off
sharesmb
String
off
Controls whether the file system is shared by using the Oracle Solaris SMB service. Otherwise. the file system is automatically shared and unshared by using the zfs share and zfs unshare commands. the sharemgr command is invoked with options that are equivalent to the contents of this property. see “Overview of ZFS Snapshots” on page 195. the file system is managed by using the legacy share and unshare commands and the dfstab file. both user data and metadata are cached. such as the sharemgr command. Controls whether a file system is available over NFS and what options are used. If set to all. If the property is set to on. Controls what is cached in the secondary cache (L2ARC). none. Controls whether the setuid bit is honored in a file system. For more information about using snapshots. The default is to restrict chown operations.
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. Possible values are all. If set to none. the sharemgr command is invoked with no options. and what options are to be used. see “Sharing and Unsharing ZFS File Systems” on page 178. If set to metadata. A file system with the sharesmb property set to off is managed through traditional tools. If set to off.zfs directory is hidden or visible in the root of the file system. If set to on.
snapdir
String
hidden
Controls whether the . the zfs share command is invoked with no options. neither user data nor metadata is cached. Otherwise. the zfs share command is invoked with options equivalent to the contents of this property.

usedbydataset
Number
off
usedbyrefreservationNumber
off
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. which would be freed if all the dataset's children were destroyed. this value is very dangerous because ZFS is ignoring the synchronous transaction demands of applications. or increased vulnerability to replay attacks. Setting this value on the currently active root or /var file system might result in out-of-spec behavior. You should only use this value if you fully understand all the associated risks. such as fsync. means that synchronous requests are disabled. which might be after many seconds. with no risk of corrupting the pool. However. The property abbreviation is usedrefreserv. which would be freed if the dataset was destroyed. O_DSYNC. Read-only property that identifies the dataset type as filesystem (file system or clone). application data loss.Introducing ZFS Properties
TABLE 6–1
ZFS Native Property Descriptions
Type Default Value
(Continued)
Description
Property Name
sync
String
standard
Determines the synchronous behavior of a file system's transactions. or snapshot. volume. disabled. File system transactions are only committed to stable storage on the next transaction group commit. always. which would be freed if the refreservation was removed. such as databases or NFS operations. The property abbreviation is usedds. ensures that every file system transaction is written and flushed to stable storage by a returning system call. Possible values are: standard. see “The used Property” on page 160. Read-only property that identifies the amount of disk space that is used by a dataset itself. This value gives the best performance. are written to the intent log. after first destroying any snapshots and removing any refreservation reservations. and so on. O_SYNC. which means synchronous file system transactions. For a detailed description. Read-only property that identifies the amount of disk space that is used by a refreservation set on a dataset. This value has a significant performance penalty.
type
String
N/A
used
Number
N/A
usedbychildren
Number
off
Read-only property that identifies the amount of disk space that is used by children of this dataset. the default value. The property abbreviation is usedchild. Read-only property that identifies the amount of disk space consumed by a dataset and all its descendents.

If this property is explicitly set to off. The default value for the utf8only property is off. The default block size for volumes is 8 KB. The block size cannot be changed after the volume has been written.
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.
version
Number
N/A
utf8only
Boolean
Off
volsize
Number
N/A
volblocksize
Number
8 KB
For volumes. it is the amount of disk space that would be freed if all of this dataset's snapshots were destroyed. because space can be shared by multiple snapshots. so set the block size at volume creation time. see “The volsize Property” on page 165. see the zfs upgrade command. For volumes. For a detailed description. For more information. which is independent of the pool version. In addition to enabling this property. The default value is off. This property cannot be changed after the file system is created. specifies the block size of the volume. specifies the logical size of the volume. This property indicates whether a file system should reject file names that include characters that are not present in the UTF-8 character code set. In particular. Any power of 2 from 512 bytes to 128 KB is valid. The property abbreviation is volblock. the normalization property must either not be explicitly set or be set to none.
vscan
Boolean
Off
Controls whether regular files should be scanned for viruses when a file is opened and closed. Identifies the on-disk version of a file system.Introducing ZFS Properties
TABLE 6–1
ZFS Native Property Descriptions
Type Default Value
(Continued)
Description
Property Name
usedbysnapshots
Number
off
Read-only property that identifies the amount of disk space that is consumed by snapshots of a dataset. The property abbreviation is usedsnap. This property can only be set to a later version that is available from the supported software release. Note that this value is not simply the sum of the snapshots' used properties. a virus scanning service must also be enabled for virus scanning to occur if you have third-party virus scanning software.

the dataset type is mentioned in the description in Table 6–1. In such cases. see “Using ZFS on a Solaris System With Zones Installed” on page 256. including the used. The read-only native properties are listed here and described in Table 6–1. usedbychildren usedbydataset usedbyrefreservation usedbysnapshots
■ ■ ■ ■
For more information about disk space accounting.
ZFS Read-Only Native Properties
Read-only native properties can be retrieved but not set. see “ZFS Disk Space Accounting” on page 64.
■ ■ ■ ■ ■ ■ ■ ■ ■ ■
available compressratio creation keystatus mounted origin referenced rekeydate type used For detailed information.
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. this property is set for any added file systems. Read-only native properties are not inherited. and available properties. For more information about using ZFS with zones installed. If this property is set. then the mount point is not honored in the global zone. When a zone is first installed. and ZFS cannot mount such a file system when requested. referenced.Introducing ZFS Properties
TABLE 6–1
ZFS Native Property Descriptions
Type Default Value
(Continued)
Description
Property Name
zoned
Boolean
N/A
Indicates whether a dataset has been added to a non-global zone.
xattr
Boolean
on
Indicates whether extended attributes are enabled (on) or disabled (off) for this file system. Some native properties are specific to a particular type of dataset. see “The used Property” on page 160.

For more information about quotas and reservations. The disk space used does not include the dataset's reservation. Pending changes are generally accounted for within a few seconds. see “ACL Property (aclinherit)” on page 221. If not specifically mentioned. Committing a change to a disk using the fsync(3c) or O_SYNC function does not necessarily guarantee that the disk space usage information will be updated immediately. and referenced does not include pending changes. their disk space is initially shared between the snapshot and the file system. and usedbysnapshots property information can be displayed with the zfs list -o space command. atime canmount
■ ■
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. Additionally. see “Out of Space Behavior” on page 64. The amount of disk space that a dataset consumes from its parent. The amount of disk space used. In such cases. The disk space that is used by a snapshot accounts for its unique data.
Settable ZFS Native Properties
Settable native properties are properties whose values can be both retrieved and set. These properties identify the used property into disk space that is consumed by descendents. as well as the amount of disk space that is freed if the dataset is recursively destroyed. is the greater of its space used and its reservation. see “Setting ZFS Quotas and Reservations” on page 181. The usedbychildren. but does consider the reservation of any descendent datasets. and possibly with previous snapshots. disk space that was previously shared becomes unique to the snapshot and is counted in the snapshot's space used.
■
aclinherit For a detailed description. For more information. clones. the dataset type is mentioned in the description in Table 6–1. settable native properties are inherited. As the file system changes. and snapshots. volumes. This value is checked against the dataset's quota and reservation. Settable native properties are set by using the zfs set command. The settable properties are listed here and described in Table 6–1. When snapshots are created. usedbyrefreservation. For more information about snapshots and space issues.Introducing ZFS Properties
The used Property
The used property is a read-only property that identifies the amount of disk space consumed by this dataset and all its descendents. Some settable native properties are specific to a particular type of dataset. as described in “Setting ZFS Properties” on page 169 or by using the zfs create command as described in “Creating a ZFS File System” on page 146. deleting snapshots can increase the amount of disk space unique to (and used by) other snapshots. a property applies to all dataset types: file systems. see Table 6–1. With the exceptions of quotas and reservations. usedbydataset. available.

except that the dataset still has a normal mountpoint property that can be inherited. When a case-insensitive matching request is made of a mixed sensitivity file system. In this case. This value setting is used by the Oracle Solaris upgrade software so that only those datasets belonging to the active boot environment are mounted at boot time.
The casesensitivity Property
This property indicates whether the file name matching algorithm used by the file system should be casesensitive. the behavior is generally the same as would be expected of a purely case-insensitive file system. you can set this property to off. the parent file system is serving as a container so that you can set properties on the container. (for example foo. FOO. and FOO. In the following example. and its canmount property is set to off. but not unique from the case-insensitive perspective. FoO. a directory might contain files foo. or allow a combination of both styles of matching (mixed). the file system cannot be mounted by using the zfs mount or zfs mount -a commands.
# zpool create userpool mirror c0t5d0 c1t6d0 # zfs set canmount=off userpool # zfs set mountpoint=/export/home userpool # zfs set compression=on userpool # zfs create userpool/user1 # zfs create userpool/user2 # zfs mount userpool/user1 /export/home/user1 userpool/user2 /export/home/user2
Setting the canmount property to noauto means that the dataset can only be mounted explicitly. fOo. establish inheritable properties for descendent file systems. /export/home. but the parent file system itself is never mounted nor is it accessible to users. For example. The difference is that a mixed sensitivity file system might contain directories with multiple names that are unique from a case-sensitive perspective. but the parent file system itself is never mounted. not automatically. For example. Exactly
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.Introducing ZFS Properties
■ ■ ■
volblocksize zoned xattr
The canmount Property
If the canmount property is set to off. caseinsensitive. Foo. and so on) one of the three existing files is chosen as the match by the matching algorithm. Properties that are set on the parent file system are inherited by descendent file systems. but the container itself is never accessible. userpool is created. If a request is made to case-insensitively match any of the possible forms of foo. Mount points for descendent user file systems are set to one common mount point. Setting this property to off is similar to setting the mountpoint property to none.

# zpool NAME export export export get all export PROPERTY size capacity altroot VALUE 33.
The dedup Property
This property controls whether duplicate data is removed from the file system. If the property is set to verify and two blocks have the same signature. This property can be enabled per file system as follows:
# zfs set dedup=on tank/home
You can use the zfs get command to determine if the dedup property is set. If the dedup property is not enabled on any dataset or if the dedup property was just enabled on the dataset. You can use the zpool get command to determine the value of the dedupratio property. normalization. Foo. foO. FOO. and casesensitivity properties also provide new permissions that can be assigned to non-privileged users by using ZFS delegated administration.00x. The result is that only unique data is stored and common components are shared between files. Setting the value to verify is equivalent to specifying sha256.Introducing ZFS Properties
which file the algorithm chooses as a match is not guaranteed.opensolaris.8G 0% SOURCE default
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. the scope is pool-wide. so long as the directory remains unchanged. For example.30x ONLINE -
The DEDUP column indicates how much deduplication has occurred. duplicate data blocks are removed synchronously. Although deduplication is set as a file system property. If a file system has the dedup property enabled. is always the same. For more information. the DEDUP ratio is 1. you can identify the deduplication ratio as follows:
# zpool list tank NAME SIZE ALLOC FREE rpool 136G 55. Do not enable the dedup property on your file systems until you have reviewed the information in this FAQ: http://hub. the dedup checksum algorithm overrides the checksum property. and so on.org/bin/view/Community+Group+zfs/dedup When dedup is enabled. ZFS does a byte-for-byte comparison with the existing block to ensure that the contents are identical.8G CAP DEDUP HEALTH ALTROOT 40% 2.2G 80. The utf8only. but what is guaranteed is that the same file is chosen as a match for any of the forms of foo. see “Delegating ZFS Permissions” on page 242.verify. The file chosen as a case-insensitive match for foo.

see “Encrypting ZFS File Systems” on page 187. Specifying a recordsize value greater than or equal to the record size of the database can result in significant performance gains.Introducing ZFS Properties
export export export export export export export export export export export export export export
health guid version bootfs delegation autoreplace cachefile failmode listsnapshots autoexpand dedupditto dedupratio free allocated
ONLINE 2064230982813446135 default 22 default default on default off default default wait default off default off default 0 default 3. ZFS automatically adjust block sizes according to internal algorithms optimized for typical access patterns.
The encryption Property
You can use the encryption property to encrypt ZFS file systems. and identifies options to be used. these algorithms might be suboptimal.
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. are replaced with underscore (_) characters. This property is designed solely for use with database workloads that access files in fixed-size records. which would be illegal in the resource name.00x 33.
The recordsize Property
The recordsize property specifies a suggested block size for files in the file system. a unique resource name is constructed from the dataset name. A pseudo property name is also supported that allows you to replace the dataset name with a specific name. Because SMB shares requires a resource name. For databases that create very large files but access the files in small random chunks. The specific name is then used to replace the prefix dataset in the case of inheritance. The size specified must be a power of 2 greater than or equal to 512 bytes and less than or equal to 128 KB. The property abbreviation is recsize. The constructed name is a copy of the dataset name except that the characters in the dataset name. Changing the file system's recordsize value only affects files created afterward. Use of this property for general purpose file systems is strongly discouraged and might adversely affect performance.
The sharesmb Property
This property enables sharing of ZFS file systems with the Oracle Solaris SMB service.6G 105M -
This pool property illustrates how much deduplication we have been able to achieve. Existing files are unaffected. For more information.

ZFS supports arbitrary user properties.
The volsize Property
The volsize property specifies the logical size of the volume. changes to volsize are not reflected in the reservation. numbers. If the new property is set to off. A volume that contains less space than it claims is available can result in undefined behavior or data corruption. When the sharesmb property is changed for a dataset. User properties have no effect on ZFS behavior. the file systems are unshared. Use extreme care when adjusting the volume size. These checks are used to prevent unexpected behavior for users. For a sparse volume. For more information about using volumes.
■
The expected convention is that the property name is divided into the following two components but this namespace is not enforced by ZFS:
module:property
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. For examples of using the sharesmb property. The maximum length of a user property name is 256 characters. only if the property was previously set to off. see “ZFS Volumes” on page 253. Though not recommended.Introducing ZFS Properties
For example. you can create a sparse volume by specifying the -s flag to zfs create -V or by changing the reservation after the volume has been created. '_'. '+'. data/home/john. see “Sharing and Unsharing ZFS File Systems” on page 178. is set to name=john. creating a volume establishes a reservation for the same amount. if the dataset. A sparse volume is a volume whose reservation is not equal to the volume size. or if they were shared before the property was changed. They must contain lowercase letters.'. or the following punctuation characters: ':'. but you can use them to annotate datasets with information that is meaningful in your environment.
ZFS User Properties
In addition to the native properties. Any changes to volsize are reflected in an equivalent change to the reservation. These effects can also occur when the volume size is changed while the volume is in use. it has a resource name of john_backups. particularly when you shrink the size. By default. the dataset and any children inheriting the property are re-shared with the new options. If a child dataset of data/home/john/backups exists. then data/home/john has a resource name of john. User property names must conform to the following conventions:
■ ■
They must contain a colon (':') character to distinguish them from native properties. depending on how the volume is used.'.

use the zfs inherit command. such as zfs list. zfs get. are reserved for use by Oracle Corporation. use a reversed DNS domain name for the module component of property names to reduce the chance that two independently developed packages will use the same property name for different purposes.
Querying ZFS File System Information
The zfs list command provides an extensible mechanism for viewing and querying dataset information. referenced. available. and mountpoint properties. zfs set.Querying ZFS File System Information
When making programmatic use of user properties. This command displays the names of all datasets on the system and the values of their used. and so on.sun. For more information about these properties. For example:
# zfs inherit -r dept:users userpool
If the property is not defined in any parent dataset. For example:
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. it is removed entirely. see “Introducing ZFS Properties” on page 149. Property names that begin with com. can be used to manipulate both native properties and user properties. Both basic and complex queries are explained in this section.
For example:
# zfs set dept:users=finance userpool/user1 # zfs set dept:users=general userpool/user2 # zfs set dept:users=itops userpool/user3
All of the commands that operate on properties. The values of user properties must conform to the following conventions:
■ ■
They must consist of arbitrary strings that are always inherited and are never validated. The maximum length of the user property value is 1024 characters. For example:
zfs get -r dept:users userpool NAME PROPERTY VALUE userpool dept:users all userpool/user1 dept:users finance userpool/user2 dept:users general userpool/user3 dept:users itops SOURCE local local local local
To clear a user property.
Listing Basic ZFS Information
You can list basic dataset information by using the zfs list command with no options.

For a list of all supported dataset properties. the -o option list can also contain the literal name to indicate that the output should include the name of the dataset.
# zfs list -o name.5G 19K /pool/home 16.81G 8K /tank/home/chua/projects/fs1 tank/home/chua/projects/fs2 8K 4. see zfs(1M).sharenfs. along with the sharenfs and mountpoint property values.5G 277K /pool/home/marks pool/home/marks@snap 0 .5G 21K /pool 16. Additionally. You can supply any dataset property as a valid argument.81G 10. -t.0K 4.mountpoint NAME SHARENFS MOUNTPOINT tank off /tank
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.81G 9.Querying ZFS File System Information
# zfs list NAME pool pool/clone pool/home pool/home/marks pool/home/marks@snap pool/test
USED 476K 18K 296K 277K 0 18K
AVAIL REFER MOUNTPOINT 16. For example:
# zfs list /pool/home/marks NAME USED AVAIL REFER MOUNTPOINT pool/home/marks 277K 16.
Creating Complex ZFS Queries
The zfs list output can be customized by using the -o.277K 16. For example:
# zfs list -r pool/home/marks NAME USED AVAIL REFER MOUNTPOINT pool/home/marks 277K 16.81G 8K /tank/home/chua/projects/fs2
For additional information about the zfs list command. see “Introducing ZFS Properties” on page 149.5G 277K /pool/home/marks . and -H options.5G 18K /test
You can also use this command to display specific datasets by providing the dataset name on the command line. You can customize property value output by using the -o option and a comma-separated list of desired properties. In addition to the properties defined.277K -
You can use the zfs list command with the mount point of a file system.5G 277K /pool/home/marks
The following example shows how to display basic information about tank/home/chua and all of its descendent datasets:
# zfs list -r tank/home/chua NAME USED AVAIL REFER MOUNTPOINT tank/home/chua 26.0K /tank/home/chua tank/home/chua/projects 16K 4. The following example uses zfs list to display the dataset name. use the -r option to recursively display all descendents of that dataset.5G 18K /pool/clone 16.0K /tank/home/chua/projects tank/home/chua/projects/fs1 8K 4.

when scripting. The following example uses the -t and -o options simultaneously to show the name and used property for all file systems:
# zfs list -t filesystem -o name. This option can be useful when you need parseable output.
TABLE 6–2 Type
Types of ZFS Datasets
Description
filesystem volume snapshot
File systems and clones Volumes Snapshots
The -t options takes a comma-separated list of the types of datasets to be displayed.used NAME USED pool 476K pool/clone 18K pool/home 296K pool/home/marks 277K pool/test 18K
You can use the -H option to omit the zfs list header from the generated output. The following example shows the output generated from using the zfs list command with the -H option:
# zfs list -H -o name pool pool/clone pool/home pool/home/marks pool/home/marks@snap pool/test
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.Querying ZFS File System Information
tank/home tank/home/ahrens tank/home/bonwick tank/home/chua tank/home/eschrock tank/home/moore tank/home/tabriz
on on on on on on ro
/tank/home /tank/home/ahrens /tank/home/bonwick /tank/home/chua legacy /tank/home/moore /tank/home/tabriz
You can use the -t option to specify the types of datasets to display. With the -H option. for example. all white space is replaced by the Tab character. The valid types are described in the following table.

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. The following four invocations of zfs set are equivalent numeric expressions that set the quota property be set to the value of 50 GB on the tank/home/marks file system:
# # # # zfs zfs zfs zfs set set set set quota=50G tank/home/marks quota=50g tank/home/marks quota=50GB tank/home/marks quota=50gb tank/home/marks
The values of non-numeric properties are case-sensitive and must be in lowercase letters. For more information about the zfs set command. The zfs set command takes a property/value sequence in the format of property=value followed by a dataset name. Any of these suffixes can be followed by an optional b. you can use the zfs create command to set properties when a dataset is created. inherit. see “Settable ZFS Native Properties” on page 160. indicating bytes. see zfs(1M).Managing ZFS Properties
Managing ZFS Properties
Dataset properties are managed through the zfs command's set.
# zfs set atime=off tank/home
In addition. The following example sets the atime property to off for tank/home. with the exception of mountpoint and sharenfs. The values of these properties can have mixed upper and lower case letters. which already indicates bytes. any file system property can be set when a file system is created. Or. For a list of settable dataset properties. For example:
# zfs create -o atime=off tank/home
You can specify numeric property values by using the following easy-to-understand suffixes (in increasing order of magnitude): BKMGTPEZ.
■ ■ ■
“Setting ZFS Properties” on page 169 “Inheriting ZFS Properties” on page 170 “Querying ZFS Properties” on page 170
Setting ZFS Properties
You can use the zfs set command to modify any settable dataset property. and get subcommands. with the exception of the B suffix. Only one property can be set or modified during each zfs set invocation.

If both had compression enabled. thus causing the value to be inherited from the parent dataset. However. the default value is used.
For more information about the zfs inherit command. the default value for the property is used. use the zfs get command to provide more detailed information in a customized format. The following example uses the zfs set command to turn on compression for the tank/home/bonwick file system. the value set in the most immediate ancestor would be used (home in this example).
Querying ZFS Properties
The simplest way to query property values is by using the zfs list command.
# zfs set compression=on tank/home/bonwick # zfs get -r compression tank NAME PROPERTY VALUE tank compression off tank/home compression off tank/home/bonwick compression on # zfs inherit compression tank/home/bonwick # zfs get -r compression tank NAME PROPERTY VALUE tank compression off tank/home compression off tank/home/bonwick compression off
SOURCE default default local SOURCE default default default
The inherit subcommand is applied recursively when the -r option is specified. The following example shows how to retrieve a single property value on a dataset:
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. In the following example. For more information. inherit their value from the parent dataset. If no ancestor has an explicit value set for an inherited property. You can use the zfs inherit command to clear a property value. for complicated queries and for scripting. see zfs(1M). Because neither home nor tank has the compression property set locally. You can use the zfs get command to retrieve any dataset property. thus causing the property to inherit the default value of off. see “Listing Basic ZFS Information” on page 166. unless a quota or reservation is explicitly set on the descendent dataset. Then. with the exception of quotas and reservations. zfs inherit is used to clear the compression property.Managing ZFS Properties
Inheriting ZFS Properties
All settable properties. the command causes the value for the compression property to be inherited by tank/home and any descendents it might have:
# zfs inherit -r compression tank/home Note – Be aware that the use of the -r option clears the current property setting for all descendent datasets.

00x yes none default none default 128K default /tank default off default on default off default on default on default on default on default off default off default hidden default restricted default on default
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. For more information about temporary mount point properties. This property value was explicitly set for this dataset by using zfs set.
TABLE 6–3
Possible SOURCE Values (zfs get Command)
Description
Source Value
default inherited from dataset-name local temporary
This property value was never explicitly set for this dataset or any of its ancestors. indicates the origin of this property value.(none)
You can use the special keyword all to retrieve all dataset property values.Managing ZFS Properties
# zfs get checksum tank/ws NAME PROPERTY tank/ws checksum
VALUE on
SOURCE default
The fourth column. This property value is inherited from the parent dataset specified in dataset-name.
.31M 66. SOURCE. The following table defines the possible source values. The default value for this property is being used. Its value is generated by ZFS. This property value was set by using the zfs mount -o option and is only valid for the duration of the mount. see “Using Temporary Mount Properties” on page 177. The following examples use the all keyword:
# zfs NAME tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank get all tank PROPERTY type creation used available referenced compressratio mounted quota reservation recordsize mountpoint sharenfs checksum compression atime devices exec setuid readonly zoned snapdir aclinherit canmount VALUE SOURCE filesystem Fri Oct 8 16:47 2010 1. This property is read-only.9G 35K 1.

temporary.
172 Oracle Solaris ZFS Administration Guide • January 2011
. the properties to display. by source type. Only properties with the specified source type are displayed. The valid source types are local.27M 0 latency off none standard off none none -
default default default default default default default default default default default default default default default
The -s option to zfs get enables you to specify. default. all temporary properties on all datasets within tank are recursively displayed:
# zfs get -r -s temporary all tank NAME PROPERTY VALUE tank/home atime off tank/home/bonwick atime off tank/home/marks atime off SOURCE temporary temporary temporary
You can query property values by using the zfs get command without specifying a target file system.
# zfs get -s local all pool NAME PROPERTY pool compression VALUE on SOURCE local
Any of the above options can be combined with the -r option to recursively display the specified properties on all children of the specified dataset. This option takes a comma-separated list indicating the desired source types. For example:
# zfs get -s local all tank/home atime tank/home/bonwick atime tank/home/marks quota off off 50G local local local
For more information about the zfs get command. In the following example. inherited. see zfs(1M).Managing ZFS Properties
tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank tank
xattr copies version utf8only normalization casesensitivity vscan nbmand sharesmb refquota refreservation primarycache secondarycache usedbysnapshots usedbydataset usedbychildren usedbyrefreservation logbias dedup mlslabel sync encryption keysource keystatus rekeydate
on 1 5 off none sensitive off off off none none all all 0 35K 1. and none. which means the command operates on all pools or file systems. The following example shows all properties that have been locally set on pool.

15G
Mounting and Sharing ZFS File Systems
This section describes how mount points and shared file systems are managed in ZFS. and -r options to retrieve the dataset name and the value of the used property for export/home and its descendents. which are designed for scripting. 1 MB would be reported as 1000000.
■
The following example shows how to retrieve a single value by using the -H and -o options of zfs get:
# zfs get -H -o value compression tank/home on
The -p option reports numeric values as their exact values.Mounting and Sharing ZFS File Systems
Querying ZFS Properties for Scripting
The zfs get command supports the -H and -o options. You can use the -H option to omit header information and to replace white space with the Tab character. to recursively retrieve the requested values for all descendents. You can use the -o option to customize the output in the following ways:
■
The literal name can be used with a comma-separated list of properties as defined in the “Introducing ZFS Properties” on page 149 section. The following example uses the -H. For example. -o. property. along with any of the preceding options.43G export/home/maybee 2. value. This option can be used as follows:
# zfs get -H -o value -p used tank/home 182983742
You can use the -r option.57G export/home/marks 1. Uniform white space allows for easily parseable data. which is a comma-separated list of properties. while omitting the header output:
# zfs get -H -o name.
■ ■ ■ ■ ■
“Managing ZFS Mount Points” on page 174 “Mounting ZFS File Systems” on page 175 “Using Temporary Mount Properties” on page 177 “Unmounting ZFS File Systems” on page 177 “Sharing and Unsharing ZFS File Systems” on page 178
Chapter 6 • Managing Oracle Solaris ZFS File Systems
173
.value -r used export/home export/home 5. and source. to be output followed by a space and an argument. name. A comma-separated list of literal fields.

If ZFS is managing a file system but it is currently unmounted. You can override the default mount point by using the zfs set command to set the mountpoint property to a specific path. The mountpoint property is inherited. You can determine specific mount-point behavior for a file system as described in this section.Mounting and Sharing ZFS File Systems
Managing ZFS Mount Points
By default. and the /etc/vfstab file must be used instead. ZFS automatically mounts the file system. if pool/home has the mountpoint property set to /export/stuff. For more information about creating pools. All ZFS file systems are mounted by ZFS at boot time by using the Service Management Facility's (SMF) svc://system/filesystem/local service.
■
Any dataset whose mountpoint property is not legacy is managed by ZFS. You can also set the default mount point for a pool's dataset at creation time by using zpool create's -m option. where path is the name of the file system. For example. File systems are mounted under /path. set the mountpoint property to none. if needed. see “Creating a ZFS Storage Pool” on page 73. ZFS automatically creates the specified mount point. a ZFS file system is automatically mounted when it is created. the file system remains unmounted. see “Legacy Mount Points” on page 175. In the following example. Doing so prevents ZFS from automatically mounting and managing a file system. In addition.
Automatic Mount Points
■
When you change the mountpoint property from legacy or none to a specific path. and the mountpoint property is changed. File systems can also be explicitly managed through legacy mount interfaces by using zfs set to set the mountpoint property to legacy. For more information about legacy mounts. see “The canmount Property” on page 162. a dataset is created whose mount point is automatically managed by ZFS:
# zfs create pool/filesystem # zfs get mountpoint pool/filesystem NAME PROPERTY VALUE
174 Oracle Solaris ZFS Administration Guide • January 2011
SOURCE
. then pool/home/user inherits /export/stuff/user for its mountpoint property value. For more information about the canmount property. ZFS file systems are automatically mounted at boot time without requiring you to edit the /etc/vfstab file. and automatically mounts the associated file system. Legacy tools including the mount and umount commands. To prevent a file system from being mounted. the canmount property can be used to control whether a file system can be mounted.

Mounting ZFS File Systems
ZFS automatically mounts file systems when file systems are created or when the system boots. ZFS does not automatically mount legacy file systems at boot time.
Legacy Mount Points
You can manage ZFS file systems with legacy tools by setting the mountpoint property to legacy.because the fsck command is not applicable to ZFS file systems. The following examples show how to set up and manage a ZFS dataset in legacy mode:
# zfs set mountpoint=legacy tank/home/eschrock # mount -F zfs tank/home/eschrock /mnt
To automatically mount a legacy file system at boot time. or explicitly mount or unmount file systems. and the ZFS mount and umount commands do not operate on datasets of this type. The following example shows what the entry in the /etc/vfstab file might look like:
#device #to mount # device to fsck mount point /mnt FS type zfs fsck pass mount mount at boot options yes -
tank/home/eschrock -
The device to fsck and fsck pass entries are set to . an error is reported.
Chapter 6 • Managing Oracle Solaris ZFS File Systems 175
. Legacy file systems must be managed through the mount and umount commands and the /etc/vfstab file. For more information about ZFS data integrity. see “Transactional Semantics” on page 51. Mount-point directories are created as needed. If ZFS is unable to unmount a file system due to it being active. you must add an entry to the /etc/vfstab file. and a forced manual unmount is necessary.Mounting and Sharing ZFS File Systems
pool/filesystem mountpoint /pool/filesystem # zfs get mounted pool/filesystem NAME PROPERTY VALUE pool/filesystem mounted yes
default SOURCE -
You can also explicitly set the mountpoint property as shown in the following example:
# zfs set mountpoint=/mnt pool/filesystem # zfs get mountpoint pool/filesystem NAME PROPERTY VALUE pool/filesystem mountpoint /mnt # zfs get mounted pool/filesystem NAME PROPERTY VALUE pool/filesystem mounted yes
SOURCE local SOURCE -
When the mountpoint property is changed. the file system is automatically unmounted from the old mount point and remounted to the new mount point. Use of the zfs mount command is necessary only when you need to change mount options.

Legacy managed mount points are not displayed. An attempt to use ZFS tools results in an error. For example:
# zfs mount tank/home/lalt cannot mount ’/export/home/lalt’: directory is not empty use legacy mountpoint to allow this behavior. Legacy managed file systems are not mounted. or use the -O flag # zfs mount -O tank/home/lalt
Legacy mount points must be managed through legacy tools. For example:
# zfs mount pool/home/billm cannot mount ’pool/home/billm’: legacy mountpoint use mount(1M) to mount this filesystem # mount -F zfs tank/home/billm
When a file system is mounted. The correlation between properties and mount options is as follows:
TABLE 6–4 Property
ZFS Mount-Related Properties and Mount Options
Mount Option
atime devices exec nbmand readonly setuid xattr
atime/noatime devices/nodevices exec/noexec nbmand/nonbmand ro/rw setuid/nosetuid xattr/noaxttr
The mount option nosuid is an alias for nodevices.
176 Oracle Solaris ZFS Administration Guide • January 2011
.nosetuid. To force a mount on top of a nonempty directory. you must use the -O option. For example:
# zfs mount -a
By default. For example:
# zfs mount tank tank/home tank/home/bonwick tank/ws /tank /tank/home /tank/home/bonwick /tank/ws
You can use the -a option to mount all ZFS managed file systems. it uses a set of mount options based on the property values associated with the dataset. ZFS does not allow mounting on top of a nonempty directory.Mounting and Sharing ZFS File Systems
The zfs mount command with no arguments shows all currently mounted file systems that are managed by ZFS.

see “ZFS and File System Mirror Mounts” on page 37. the read-only mount option is temporarily set on the tank/home/perrin file system. If a property value is changed while the dataset is mounted.noatime tank/home/perrin # zfs get atime tank/home/perrin NAME PROPERTY VALUE tank/home/perrin atime off
SOURCE temporary
For more information about the zfs mount command. In the following example.
Unmounting ZFS File Systems
You can unmount ZFS file systems by using the zfs unmount subcommand.
Using Temporary Mount Properties
If any of the mount options described in the preceding section are set explicitly by using the-o option with the zfs mount command.
# zfs unmount tank/home/eschrock cannot unmount ’/export/home/eschrock’: Device busy # zfs unmount -f tank/home/eschrock
Chapter 6 • Managing Oracle Solaris ZFS File Systems 177
. In the following example. These property values are reported as temporary by the zfs get command and revert back to their original values when the file system is unmounted. you can use the -f option. a file system is unmounted by its file system name:
# zfs unmount tank/home/tabriz
In the following example. In the following example. Unpredictable application behavior can result. For a description of mirror mounts. overriding any temporary setting. the associated property value is temporarily overridden. see zfs(1M). The unmount command can take either the mount point or the file system name as an argument. The file system is assumed to be unmounted. Be cautious when forcibly unmounting a file system if its contents are actively being used.Mounting and Sharing ZFS File Systems
You can use the NFSv4 mirror mount features to help you better manage NFS-mounted ZFS home directories.
# zfs mount -o ro tank/home/perrin
To temporarily change a property value on a file system that is currently mounted. the atime property is temporarily changed to off for a file system that is currently mounted:
# zfs mount -o remount. you must use the special remount option. To forcibly unmount a file system. the file system is unmounted by its mount point:
# zfs unmount /export/home/tabriz
The unmount command fails if the file system is busy. the change takes effect immediately.

and file systems are automatically shared on creation if their inherited property is not off. For example:
# zfs unshare tank/home/tabriz
This command unshares the tank/home/tabriz file system. you do not have to modify the /etc/dfs/dfstab file when a new file system is shared. all file systems are unshared. see zfs(1M). The value off indicates that the file system is not managed by ZFS and can be shared through traditional means. All file systems whose sharenfs property is not off are shared during boot. For example:
# umount /export/home/bob
For more information about the zfs umount command. tank/home/tabriz is shared as read-only regardless of the sharenfs property that is set for tank/home. file systems sometimes need to be explicitly unshared. the legacy umount command can be used to unmount ZFS file systems. After the property is set to ro (read only). For example:
# # # # zfs zfs zfs zfs set sharenfs=on tank/home create tank/home/bricker create tank/home/tabriz set sharenfs=ro tank/home/tabriz
Both tank/home/bricker and tank/home/tabriz are initially shared as writable because they inherit the sharenfs property from tank/home.
Unsharing ZFS File Systems
Although most file systems are automatically shared or unshared during boot. and destruction. creation. To unshare all ZFS file systems on the system.
Controlling Share Semantics
By default. such as the /etc/dfs/dfstab file.
Sharing and Unsharing ZFS File Systems
ZFS can automatically share file systems by setting the sharenfs property. The sharenfs property is a comma-separated list of options to pass to the share command. which provides read/write permissions to anyone. use the zfs unshare command. use zfs set syntax similar to the following:
# zfs set sharenfs=on tank/home/eschrock
The sharenfs property is inherited. To share a new file system.Mounting and Sharing ZFS File Systems
To provide for backward compatibility. The value on is an alias for the default share options. To do so. you need to use the -a option.
178 Oracle Solaris ZFS Administration Guide • January 2011
. Using this property.

which has multiple instances. see “The sharesmb Property” on page 164. If necessary.
Sharing ZFS Files in an Oracle Solaris SMB Environment
The sharesmb property is provided to share ZFS files by using the Oracle Solaris SMB software product. This value enables you to administer file system sharing through traditional means. you unshare a file system.
# svcadm enable -r smb/server svcadm: svc:/milestone/network depends on svc:/network/physical. you can manually share a file system with options that differ from the options of the sharenfs property. a ZFS file system sandbox/fs1 is created and shared with the sharesmb property. the automatic behavior of ZFS with respect to sharing file system on boot and creation is sufficient for normal operations. This administrative model is discouraged. these shares are visible to SMB client systems. Choose to manage NFS shares either completely through ZFS or completely through the /etc/dfs/dfstab file. When this property is set on a ZFS file system. If. For more information about using the Oracle Solaris SMB software product.
EXAMPLE 6–1
Example—Sharing ZFS File Systems (sharesmb)
In this example. see the System Administration Guide: Windows Interoperability. then ZFS does not attempt to share or unshare the file system at any time. such as the /etc/dfs/dfstab file.Mounting and Sharing ZFS File Systems
# zfs unshare -a
Sharing ZFS File Systems
Most of the time. For a detailed description of the sharesmb property. for some reason. the legacy share and unshare commands can still function on ZFS file systems. For example:
# zfs share tank/home/tabriz
You can also share all ZFS file systems on the system by using the -a option.
# zfs share -a
Legacy Share Behavior
If the sharenfs property is set to off. As a result. Unlike the legacy mount command. you can share it again by using the zfs share command. The ZFS administrative model is designed to be simpler and less work than the traditional model. # svcs | grep smb online 10:47:15 svc:/network/smb/server:default
Chapter 6 • Managing Oracle Solaris ZFS File Systems 179
. enable the SMB services.

you can use the reservation property to guarantee that a specified amount of disk space is available to a file system. Consider the following points to determine which quota and reservation features might best help you manage your file systems:
■
The quota and reservation properties are convenient for managing disk space consumed by datasets and their descendents. if a quota is set on the tank/home dataset. but the descendents have their dataset name appended to the resource name.
181
■
Chapter 6 • Managing Oracle Solaris ZFS File Systems
. That is. on a file system before file system version 4. The refquota and refreservation properties are appropriate for managing disk space consumed by datasets. The user and group quota properties cannot be set on a volume. such as snapshots and clones. or on a pool before pool version 15.
# sharemgr show -vp default nfs=() zfs nfs=() zfs/sandbox smb=() sandbox=/sandbox sandbox_fs1=/sandbox/fs1 sandbox_fs2=/sandbox/fs2
smb=() smb=()
Setting ZFS Quotas and Reservations
You can use the quota property to set a limit on the amount of disk space a file system can use.Setting ZFS Quotas and Reservations
EXAMPLE 6–1
Example—Sharing ZFS File Systems (sharesmb)
(Continued)
# # # #
zpool create sandbox mirror c0t2d0 c0t4d0 zfs set sharesmb=on sandbox zfs create sandbox/fs1 zfs create sandbox/fs2
The top-level file system has a resource name of sandbox. In addition. The amount of disk space used by a dataset and all of its descendents is reported by the used property. you can set a user or a group quota on the amount of disk space consumed by files that are owned by a particular user or group. Similarly. tank/home and all of its descendents draw from that reservation. The refquota and refreservation properties are used to manage file system space without accounting for disk space consumed by descendents. Both properties apply to the dataset on which they are set and all descendents of that dataset. In this Solaris release. if tank/home is given a reservation. the total amount of disk space used by tank/home and all of its descendents cannot exceed the quota.

You cannot set a quota to an amount less than is currently being used by a dataset. For example:
# zfs list NAME USED tank/home 16. If you set the quota or refquota property.5 GB of disk space available.0K tank/home/bonwick/ws 6. a quota of 10 GB is set on tank/home/bonwick:
# zfs set quota=10G tank/home/bonwick # zfs get quota tank/home/bonwick NAME PROPERTY VALUE tank/home/bonwick quota 10. For example. For example:
# zfs set quota=10K tank/home/bonwick cannot set quota for ’tank/home/bonwick’: size is less than current used or reserved space
You can set a refquota on a dataset that limits the amount of disk space that the dataset can consume.0G
SOURCE local
Quotas also affect the output of the zfs list and df commands.5K tank/home/bonwick 15. due to the quota on tank/home/bonwick.50K # df -h /export/home/bonwick Filesystem size tank/home/bonwick 10G AVAIL 33. It is possible to a exceed a quota that is greater than the refquota.0G REFER 8. This hard limit does not include disk space that is consumed by descendents.50K 8.0G 10.50K 8. see “Setting Quotas on ZFS File Systems” on page 182 and “Setting Reservations on ZFS File Systems” on page 185. User and group quotas provide a way to more easily manage disk space with many user accounts. For example:
# zfs set refquota=10g students/studentA # zfs list NAME USED AVAIL REFER MOUNTPOINT
182 Oracle Solaris ZFS Administration Guide • January 2011
.5G 10.
Setting Quotas on ZFS File Systems
Quotas on ZFS file systems can be set and displayed by using the zfs set and zfs get commands. operations that try to exceed either value fail. such as in a university environment.
■
For more information about setting quotas and reservations.50K MOUNTPOINT /export/home /export/home/bonwick /export/home/bonwick/ws
used avail capacity Mounted on 8K 10G 1% /export/home/bonwick
Note that although tank/home has 33. In the following example. if some snapshot blocks are modified. you might actually exceed the quota before you exceed the refquota. tank/home/bonwick and tank/home/bonwick/ws each have only 10 GB of disk space available.Setting ZFS Quotas and Reservations
■
Setting the refquota or refreservation property higher than the quota or reservation property has no effect.

7M 33. studentA might reach the refquota (10 GB) hard limit. For example:
# # # # zfs zfs zfs zfs create students/compsci set userquota@student1=10G students/compsci create students/labstaff set groupquota@staff=20GB students/labstaff
Display the current user quota or group quota as follows:
# zfs get userquota@student1 students/compsci NAME PROPERTY VALUE students/compsci userquota@student1 10G # zfs get groupquota@staff students/labstaff NAME PROPERTY VALUE students/labstaff groupquota@staff 20G SOURCE local SOURCE local
You can display general user or group disk space usage by querying the following properties:
Chapter 6 • Managing Oracle Solaris ZFS File Systems 183
.quota students/studentA NAME PROPERTY VALUE students/studentA refquota 10G students/studentA quota 20G SOURCE local local
Setting User and Group Quotas on a ZFS File System
You can set a user quota or a group quota by using the zfs userquota or zfs groupquota commands. the smaller of the two quotas (10 GB as compared to 20 GB) is displayed in the zfs list output. respectively.94G students/studentA@today 0 -
/profs /students /students/studentA REFER 18K 19K 57.5M # zfs snapshot students/studentA@today # zfs list NAME USED AVAIL profs 106K 33.2G students 57.5M -
In this scenario. In the preceding example.7M 33. For example:
# zfs get refquota.Setting ZFS Quotas and Reservations
profs 106K 33. you can set another quota on a dataset to help manage the disk space that is consumed by snapshots.2G students/studentA 57.5M 9.5M /students/studentA students/studentA@today 0 .7M 33.2G 19K /students students/studentA 57.5M 9. use the zfs get command.94G 57.2G 18K /profs students 57.94G 57. To view the value of both quotas.2G 18K students 57. For example:
# zfs set quota=20g students/studentA # zfs list NAME USED AVAIL REFER MOUNTPOINT profs 106K 33.5M 9.5M 57. but studentA can remove files to recover.5M MOUNTPOINT /profs /students /students/studentA -
For additional convenience.57. even if snapshots exist.2G 19K students/studentA 57.

However. can access everyone's user or group disk space accounting information. Without any options. which displays a list of all of the other file system properties. a user or group quota is included with the file system when a stream is created by using the zfs send command. For example:
# zfs set userquota@student1=10m students/compsci # zfs userspace students/compsci TYPE NAME USED QUOTA
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. even without the -R option. or on a pool prior to pool version 15. the user or group quota is applied when a clone or a snapshot is created from a file system that has a user or group quota.
■
■
■
Enforcement of user and group quotas might be delayed by several seconds. on a file system prior to file system version 4. You can remove a user quota or group quota as follows:
# zfs set userquota@user1=none students/compsci # zfs set groupquota@staff=none students/labstaff
User and group quotas on ZFS file systems provide the following features:
■
A user quota or group quota that is set on a parent file system is not automatically inherited by a descendent file system. The userquota and groupquota properties cannot be set on ZFS volumes. for example. This delay means that users might exceed their quota before the system notices that they are over quota and refuses additional writes with the EDQUOT error message. the quota command only displays output if the user's quota is exceeded. You can use the legacy quota command to review user quotas in an NFS environment. Likewise. Unprivileged users can only access their own disk space usage. query the following properties:
# zfs get userused@student1 students/compsci NAME PROPERTY VALUE students/compsci userused@student1 455M # zfs get groupused@staff students/labstaff NAME PROPERTY VALUE students/labstaff groupused@staff 217M SOURCE local SOURCE local
The user and group quota properties are not displayed by using the zfs get all dataset command.Setting ZFS Quotas and Reservations
# zfs TYPE POSIX POSIX # zfs TYPE POSIX POSIX
userspace students/compsci NAME USED QUOTA User root 227M none User student1 455M 10G groupspace students/labstaff NAME USED QUOTA Group root 217M none Group staff 217M 20G
To identify individual user or group disk space usage. The root user or a user who has been granted the userused or groupused privilege. where a ZFS file system is mounted.

The total amount of all outstanding.50K /export/home 15.5G 8. For example:
# zfs set userquota@student1=10GB students/compsci # zfs userspace students/compsci TYPE NAME USED QUOTA POSIX User root 227M none POSIX User student1 455M 10G # quota student1 # quota -v student1 Disk quotas for student1 (uid 201): Filesystem usage quota limit timeleft files quota limit /students/compsci 466029 10485760 10485760
timeleft
Setting Reservations on ZFS File Systems
A ZFS reservation is an allocation of disk space from the pool that is guaranteed to be available to a dataset. unconsumed reservations cannot exceed the amount of unused disk space in the pool. For example:
# zfs set reservation=5G tank/home/moore # zfs get reservation tank/home/moore NAME PROPERTY VALUE SOURCE tank/home/moore reservation 5G local
Reservations can affect the output of the zfs list command.00G 33. The used space reflects the space reserved for tank/home/moore. ZFS reservations can be set and displayed by using the zfs set and zfs get commands. you can use the quota -v command to review the user's quota. you cannot reserve disk space for a dataset if that space is not currently available in the pool.5G 8. Reservations are considered in the used disk space calculation of the parent dataset and do count against its quota. reservation.50K /export/home/moore
Note that tank/home is using 5 GB of disk space. As such. although the total amount of space referred to by tank/home and its descendents is much less than 5 GB. For example:
# zfs list NAME tank/home tank/home/moore USED AVAIL REFER MOUNTPOINT 5.
# zfs set quota=5G pool/filesystem # zfs set reservation=10G pool/filesystem/user1 cannot set reservation for ’pool/filesystem/user1’: size is greater than available space
Chapter 6 • Managing Oracle Solaris ZFS File Systems 185
.Setting ZFS Quotas and Reservations
POSIX User root 227M none POSIX User student1 455M 10M # quota student1 Block limit reached on /students/compsci
If you reset the user quota and the quota limit is no longer exceeded. or both.0K 33.

2G 18K /profs/prof1
Regular reservations are accounted for in the parent's used space calculation. For example:
# zfs set reservation=20g profs/prof1 # zfs list NAME USED AVAIL REFER MOUNTPOINT profs 20. For example:
# zfs get reservation. That is. Rather. and the dataset's current usage is below its quota. use the zfs get command. Reservations are not cumulative.refreserv profs/prof1 NAME PROPERTY VALUE SOURCE profs/prof1 reservation 20G local profs/prof1 refreservation 10G local
If refreservation is set. In the preceding example. For example:
# zfs set refreservation=10g profs/prof1 # zfs list NAME USED AVAIL REFER MOUNTPOINT profs 10. a second invocation of zfs set to set a reservation does not add its reservation to the existing reservation.2G 19K /profs profs/prof1 10G 33.0G 23. For example:
# zfs set reservation=10G tank/home/moore # zfs set reservation=5G tank/home/moore # zfs get reservation tank/home/moore NAME PROPERTY VALUE tank/home/moore reservation 5. This reservation is accounted for in the parent dataset's space used calculation. the smaller of the two quotas (10 GB as compared to 20 GB) is displayed in the zfs list output.00G
SOURCE local
You can set a refreservation reservation to guarantee disk space for a dataset that does not include disk space consumed by snapshots and clones. a snapshot is only allowed if sufficient unreserved pool space exists outside of this reservation to accommodate the current number of referenced bytes in the dataset.Setting ZFS Quotas and Reservations
A dataset can use more disk space than its reservation. the second reservation replaces the first reservation. A dataset cannot consume disk space that has been reserved for another dataset.
186 Oracle Solaris ZFS Administration Guide • January 2011
.2G 19K /profs profs/prof1 10G 33. To view the value of both quotas.0G 13.2G 18K /profs/prof1
You can also set a reservation on the same dataset to guarantee dataset space and snapshot space. as long as unreserved space is available in the pool. and counts against the parent dataset's quotas and reservations.

The benefits of using ZFS encryption are as follows:
■
ZFS encryption is integrated with the ZFS command set.
■
■
■
■
You can set an encryption policy when a ZFS dataset is created. The format and location of the wrapping key are specified in the keysource property as follows:
keysource=format. ZFS encryption is inheritable to descendent file systems. ZFS encryption uses the Oracle Solaris Cryptographic Framework. encryption operations such as key changes and rekey are performed online.hex — A hexidecimal key string passphrase — A character string that generates a key
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. For example. as in the above example when the encrypted file system is created.Encrypting ZFS File Systems
Encrypting ZFS File Systems
Encryption is the process where data is encoded for privacy and a key is needed by the data owner to access the encoded data. A wrapping key is either in a file (in raw or hex format) or it is derived from a passphrase. A wrapping key is used to encrypt the actual data encryption keys. Key management can be delegated through ZFS delegated administration Data is encrypted using AES (Advanced Encryption Standard) with key lengths of 128 . The default encryption policy is to prompt for a passphrase. to the kernel. You have the flexibility of encrypting specific file systems.
# zfs create -o encryption=on tank/home/darren Enter passphrase for ’tank/home/darren’: xxxxxxx Enter again: xxxxxxxx
Confirm that the file system has encryption enabled. and 256 in the CCM and GCM operation modes. which must be a minimum of 8 characters in length. Like other ZFS operations. For example:
# zfs get encryption tank/home/darren NAME PROPERTY VALUE tank/home/darren encryption on SOURCE local
The default encryption algorithm is aes-128-ccm when a file system's encryption value is on. the tank/home/darren file system is created with the encryption property enabled. The wrapping key is passed from the zfs command.192.location
■
Format is one of the following:
■ ■ ■
raw — The raw key bytes . You can use your existing storage pools as long as they are upgraded. which gives it access to any available hardware acceleration or optimized software implementations of the encryption algorithms automatically. but the policy cannot be changed.

then the wrapping key is derived from the passphrase. then consider the following points:
■
Currently. When a file system's keysource property values identifies passphrase. you cannot send an unencrypted dataset stream and receive it as an encrypted stream even if the receiving pool's dataset has encryption enabled.Encrypting ZFS File Systems
■
Location is one of the following:
■ ■
prompt — You are prompted for a key when the file system is created or mounted . Otherwise. The existing wrapping key must have been loaded first. as raw bytes or in hexidecimal format. which is likely only suitable for scripting. For example:
# zfs snapshot tank/home/darren@now # zfs clone tank/home/darren@now tank/home/darren-new Enter passphrase for ’tank/home/darren-new’: xxxxxxx Enter again: xxxxxxxx # zfs set encryption=off tank/home/darren-new cannot set property for ’tank/home/darren-new’: ’encryption’ is readonly
If you need to copy or migrate encrypted or unencrypted ZFS file systems. either at boot time or by explicitly loading the file system key (zfs key -l) or by mounting the file system (zfs mount filesystem).file:///filename — The key file location in a file system
If the keysource format is passphrase. For example:
188 Oracle Solaris ZFS Administration Guide • January 2011
. For more information. the keysource property value points to the actual wrapping key. A file system's encryption policy is inherited by descendent file systems and cannot be removed. then the wrapping key is derived from the passphrase using PKCS#5 PBKD2 and a per file system randomly generated salt. This means that the same passphrase generates a different wrapping key if used on descendent datasets. You can use the following commands to migrate unencrypted data to a pool/dataset with encryption enabled:
■ ■ ■ ■
■
cp -r find | cpio tar rsync
■
A replicated encrypted dataset stream can be received into a encrypted dataset and the data remains encrypted.
Changing an Encrypted ZFS File System's Keys
You can change an encrypted file system's wrapping key by using the zfs key -c command. You can specify that the passphrase is stored in a file or stored in a raw stream of bytes that are prompted for. see Example 6–5.

aes-256-gcm
The ZFS keysource property identifies the format and location of the key that wraps the file system's data encryption keys.file:///media/stick/key tank/home/darren
The data encryption key for an encrypted file system can be changed by using the zfs key -K command. aes-192-ccm. The following encryption algorithms are available:
■ ■
aes-128-ccm. the data encryption key is not visible nor is it directly managed by you.Encrypting ZFS File Systems
# zfs key -c tank/home/darren Enter new passphrase for ’tank/home/darren’: xxxxxxxx Enter again: xxxxxxxx
In the following example. For example:
# zfs key -K tank/home/darren
In the above example. For example:
# zfs get rekeydate tank/home/darren NAME PROPERTY VALUE SOURCE tank/home/darren rekeydate Tue Oct 12 15:36 2010 local
If an encrypted file system's creation and rekeydate properties have the same value. In most cases. the wrapping key is changed and the keysource property value is changed to specify that the wrapping key comes from a file.prompt local
The ZFS rekeydate property identifies the date of the last zfs key -K operation. In addition. Changing a dataset key by using the zfs key -c and zfs key -K commands require the keychange permission. This feature can be used to provide compliance with NIST 800-57 guidelines on a data encryption key's time limit. but the new encryption key is only used for newly written data.
# zfs key -c -o keysource=raw. the file system has never been rekeyed by an zfs key -K operation. aes-256-ccm aes-128-gcm. aes-192-gcm.
Delegating ZFS Key Operation Permissions
Review the following permission descriptions for delegating key operations:
■
Loading or unloading a dataset key by using the zfs key -l and zfs key -u commands require the key permission. you need the keychange delegation to perform a key change operation. you will need the mount permission as well. For example:
# zfs get keysource tank/home/darren NAME PROPERTY VALUE SOURCE tank/home/darren keysource passphrase.
189
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Chapter 6 • Managing Oracle Solaris ZFS File Systems
.

if possible. the checksum is verified and the data is decrypted. the file system is not mounted automatically. Or. you will need to either explicitly mount it with the zfs mount command and specify the passphrase or use the zfs key -l command to be prompted for the key after the system is booted. and Encryption Properties
Review the following considerations when using the ZFS compression.
■
■
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Oracle Solaris ZFS Administration Guide • January 2011
.prompt at boot time. if required. For example:
# zfs Enter Enter Enter mount -a passphrase for ’tank/home/darren’: xxxxxxxx passphrase for ’tank/home/ws’: xxxxxxxx passphrase for ’users/home/marks’: xxxxxxxx
■
■
If an encrypted file system's keysource property points to a file in another file system. and the checksum is verified. For example. This model also allows you to build a key escrow system. If the dedup property is enabled on an encrypted dataset that is also cloned and the zfs key -Kor zfs clone -K commands have not been used on the clones. and encryption properties:
■
When a file is written. particularly if the file is on removable media.
Interactions Between ZFS Compression. which allows you to have a two-person key operation model. Deduplication. For example. determine which users can use the keys verses which users can change them. encrypted. data from all the clones will be deduplicated. if possible.Encrypting ZFS File Systems
Consider delegating separate permissions for key use (load or unload) and key change.
Mounting an Encrypted ZFS File System
Review the following considerations when attempting to mount an encrypted ZFS file system:
■
If an encrypted file system key is not available during boot time. When a file is read. the data is decompressed. Then.prompt will not mount during boot time because the boot process is not interrupted to prompt for a passphrase. If you want to mount a file system with an encryption policy set to passphrase. Then. the data is deduplicated. the data is compressed. deduplication. the mount order of the file systems can impact whether the encrypted file system is mounted at boot. both users need to be present for a key change. a file system with an encryption policy set to passphrase.

you are not prompted for a key when cloning a descendent of an encrypted file system.file tank/home/cindys
EXAMPLE 6–3
Encrypting a ZFS File System With a Different Encryption Algorithm
You can create a ZFS storage pool and have all the file systems in the storage pool inherit an encryption algorithm.
# pktool genkey keystore=file outkey=/cindykey. the users/home/marks file system is created and encrypted by using the aes-256-ccm encryption algorithm.file is specified when the tank/home/cindy file system is created. and you are not prompted for a new passphrase if keysource=passphrase.Encrypting ZFS File Systems
Examples of Encrypting ZFS File Systems
EXAMPLE 6–2
Encrypting a ZFS File System by Using a Raw Key
In the following example.
# zpool create -O encryption=on users mirror c0t1d0 c1t1d0 mirror c2t1d0 c3t1d0 Enter passphrase for ’users’: xxxxxxxx Enter again: xxxxxxxx # zfs create users/home # zfs get encryption users/home NAME PROPERTY VALUE SOURCE users/home encryption on inherited from users # zfs create -o encryption=aes-256-ccm users/home/marks # zfs get encryption users/home/marks NAME PROPERTY VALUE SOURCE users/home/marks encryption aes-256-ccm local
EXAMPLE 6–4
Cloning an Encrypted ZFS File System
If the clone dataset inherits the keysource property from the same dataset as its origin snapshot. In this example.file keytype=aes keylen=256
Then. the users pool is created and the users/home file system is created and encrypted by using a passphrase. then a new keysource is not necessary.file:///cindykey. The same keysource is used for the clone. Then. an aes-256-ccm encryption key is generated by using the pktool command and is written to a file. For example: By default.
# zfs Enter Enter # zfs # zfs # zfs create -o encryption=on tank/ws passphrase for ’tank/ws’: xxxxxxxx again: xxxxxxxx create tank/ws/fs1 snapshot tank/ws/fs1@snap1 clone tank/ws/fs1@snap1 tank/ws/fs1clone
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Chapter 6 • Managing Oracle Solaris ZFS File Systems
.file. The default encryption algorithm is aes-128-ccm.prompt. /cindykey. the /cindykey.
# zfs create -o encryption=aes-256-ccm -o keysource=raw.

the tank/home/darren@snap1 snapshot is created from the encrypted /tank/home/darren file system.
# zfs get encryption tank/home/darren NAME PROPERTY VALUE SOURCE tank/home/darren encryption on local # zfs snapshot tank/home/darren@snap1 # zfs get encryption bpool/snaps NAME PROPERTY VALUE SOURCE bpool/snaps encryption on inherited from bpool # zfs send tank/home/darren@snap1 | zfs receive bpool/snaps/darren1012 # zfs get encryption bpool/snaps/darren1012 NAME PROPERTY VALUE SOURCE bpool/snaps/darren1012 encryption on inherited from bpool
In this case. However. with the encryption property enabled so the resulting received data is encrypted. If you clone an encrypted file system rather than a descendent encrypted file system. the tank/home/darren@snap1 stream is not encrypted during the send process.
192 Oracle Solaris ZFS Administration Guide • January 2011
. this command notifies you when your file systems are running older versions. you are prompted to provide a new key. the snapshot is sent to bpool/snaps. For example. this file system is at the current version 5.
Use this command to identify the features that are available with each file system version. In addition. All filesystems are formatted with the current version. use the zfs clone -K command.
# zfs upgrade This system is currently running ZFS filesystem version 5. Then. For example:
# zfs Enter Enter # zfs # zfs Enter Enter create -o encryption=on tank/ws passphrase for ’tank/ws’: xxxxxxxx again: xxxxxxxx snapshot tank/ws@1 clone tank/ws@1 tank/ws1clone passphrase for ’tank/ws1clone’: xxxxxxxx again: xxxxxxxx Sending and Receiving an Encrypted ZFS File System
EXAMPLE 6–5
In the following example.
Upgrading ZFS File Systems
If you have ZFS file systems from a previous Solaris release. you can upgrade your file systems with the zfs upgrade command to take advantage of the file system features in the current release. a new key is automatically generated for the received encrypted dataset.Upgrading ZFS File Systems
EXAMPLE 6–4
Cloning an Encrypted ZFS File System
(Continued)
If you want to create a new key for the clone file system.

the snapshot consumes disk space by continuing to reference the old data. as data within the active dataset changes. Snapshots use no separate backing store. The following sections are provided in this chapter:
■ ■ ■ ■ ■ ■ ■ ■ ■ ■
“Overview of ZFS Snapshots” on page 195 “Creating and Destroying ZFS Snapshots” on page 196 “Displaying and Accessing ZFS Snapshots” on page 199 “Rolling Back a ZFS Snapshot” on page 200 “Managing Automatic ZFS Snapshots” on page 202 “Overview of ZFS Clones” on page 205 “Creating a ZFS Clone” on page 205 “Destroying a ZFS Clone” on page 206 “Replacing a ZFS File System With a ZFS Clone” on page 206 “Sending and Receiving ZFS Data” on page 207
Overview of ZFS Snapshots
A snapshot is a read-only copy of a file system or volume. Snapshots can be created almost instantly.C H A P T E R
Working With Oracle Solaris ZFS Snapshots and Clones
7
7
This chapter describes how to create and manage Oracle Solaris ZFS snapshots and clones. Snapshots consume disk space directly from the same storage pool as the file system or volume from which they were created. However. The theoretical maximum number of snapshots is 264. Information about saving snapshots is also provided.
195
. thus preventing the disk space from being freed. ZFS snapshots include the following features:
■ ■ ■
The persist across system reboots. and they initially consume no additional disk space within the pool.

156M tank/home/bob@now 0 . see “Sending and Receiving ZFS Data” on page 207. which takes as its only argument the name of the snapshot to create. The benefit of atomic snapshot operations is that the snapshot data is always taken at one consistent time.Overview of ZFS Snapshots
■
Recursive snapshots are created quickly as one atomic operation.259M tank/home/anne@now 0 .
Snapshots of volumes cannot be accessed directly.4. Nor can dataset properties be applied to a snapshot. even across descendent file systems. The snapshot name is specified as follows:
filesystem@snapname volume@snapname
The snapshot name must satisfy the naming requirements in “ZFS Component Naming Requirements” on page 55.3M . In the following example. For example:
# zfs snapshot -r tank/home@now # zfs list -t snapshot NAME USED AVAIL REFER MOUNTPOINT rpool/ROOT/zfs2BE@zfs2BE 78. For information about backing up a ZFS snapshot. The snapshots are created together (all at once) or not created at all. For example:
# zfs set compression=on tank/home/ahrens@now cannot set compression property for ’tank/home/ahrens@now’: snapshot properties cannot be modified
Snapshots are destroyed by using the zfs destroy command.53G tank/home@now 0 26K tank/home/ahrens@now 0 . backed up.
# zfs snapshot tank/home/ahrens@friday
You can create snapshots for all descendent file systems by using the -r option.104M -
Snapshots have no modifiable properties. rolled back to. but they can be cloned. a snapshot of tank/home/ahrens that is named friday is created. For example:
# zfs destroy tank/home/ahrens@now
196 Oracle Solaris ZFS Administration Guide • January 2011
.156M tank/home/cindys@now 0 . and so on.
■ ■ ■
“Creating and Destroying ZFS Snapshots” on page 196 “Displaying and Accessing ZFS Snapshots” on page 199 “Rolling Back a ZFS Snapshot” on page 200
Creating and Destroying ZFS Snapshots
Snapshots are created by using the zfs snapshot command.

Each snapshot has an associated user-reference count. In addition. keep.
Holding ZFS Snapshots
If you have different automatic snapshot policies such that older snapshots are being inadvertently destroyed by zfs receive because they no longer exist on the sending side. see “Destroying a ZFS File System” on page 147. In this Solaris release. attempts to destroy that held snapshot by using the zfs destroy command will fail. the following syntax puts a hold tag. to the given snapshot or set of snapshots. In the previous Solaris release. a snapshot could only be destroyed by using the zfs destroy command if it had no clones. You can hold a snapshot or set of snapshots. Holding a snapshot prevents it from being destroyed. on tank/home/cindys/snap@1. if clones have been created from a snapshot. For example:
# zfs destroy tank/home/cindys@snap1 cannot destroy ’tank/home/cindys@snap1’: dataset is busy
Chapter 7 • Working With Oracle Solaris ZFS Snapshots and Clones 197
. keep. This count increases by one whenever a hold is put on a snapshot and decreases by one whenever a hold is released.Overview of ZFS Snapshots
A dataset cannot be destroyed if snapshots of the dataset exist. Each snapshot has its own tag namespace and hold tags must be unique within that space. For example:
# zfs destroy tank/home/ahrens cannot destroy ’tank/home/ahrens’: filesystem has children use ’-r’ to destroy the following datasets: tank/home/ahrens@tuesday tank/home/ahrens@wednesday tank/home/ahrens@thursday
In addition.
# zfs hold keep tank/home/cindys@snap1
You can use the -r option to recursively hold the snapshots of all descendent file systems. you might consider using the snapshots hold feature. this feature allows a snapshot with clones to be deleted pending the removal of the last clone by using the zfs destroy -d command. then they must be destroyed before the snapshot can be destroyed. the snapshot must also have a zero user-reference count. which is initialized to zero. For example:
# zfs snapshot -r tank/home@now # zfs hold -r keep tank/home@now
This syntax adds a single reference. For more information about the destroy subcommand. For example. If a hold exists on a snapshot.

■
Renaming ZFS Snapshots
You can rename snapshots. For example:
# zfs release -r keep tank/home@now
If the snapshot is released. also referred to as the user-reference count. use the -d option. the snapshot can be destroyed by using the zfs destroy command. The userrefs property is set to the number of holds on this snapshot. the following shortcut syntax is equivalent to the preceding syntax:
# zfs rename tank/home/cindys@083006 today
The following snapshot rename operation is not supported because the target pool and file system name are different from the pool and file system where the snapshot was created:
# zfs rename tank/home/cindys@today pool/home/cindys@saturday cannot rename to ’pool/home/cindys@today’: snapshots must be part of same dataset
198 Oracle Solaris ZFS Administration Guide • January 2011
. Otherwise. For example:
# zfs rename tank/home/cindys@083006 tank/home/cindys@today
In addition. the property is off. For example:
# zfs holds tank/home@now NAME TAG TIMESTAMP tank/home@now keep Thu Jul 15 11:25:39 2010 # zfs holds -r tank/home@now NAME TAG TIMESTAMP tank/home/cindys@now keep Thu Jul 15 11:25:39 2010 tank/home/mark@now keep Thu Jul 15 11:25:39 2010 tank/home@now keep Thu Jul 15 11:25:39 2010
You can use the zfs release command to release a hold on a snapshot or set of snapshots. For example:
# zfs destroy -d tank/home/cindys@snap1
Use the zfs holds command to display a list of held snapshots. For example:
# zfs destroy -r tank/home@now
Two new properties identify snapshot hold information:
■
The defer_destroy property is on if the snapshot has been marked for deferred destruction by using the zfs destroy -d command.Overview of ZFS Snapshots
If you want to destroy a held snapshot. but they must be renamed within the same pool and dataset from which they were created.

New read-only file system properties describe disk space usage for clones. As the file system changes.50K
.
200 Oracle Solaris ZFS Administration Guide • January 2011
.524K -
You can list snapshots that were created for a particular file system as follows:
# zfs list -r -t snapshot -o name.
Rolling Back a ZFS Snapshot
You can use the zfs rollback command to discard all changes made to a file system since a specific snapshot was created.79G 6.29G 6. For example:
$ zfs list -o space NAME AVAIL rpool 25.77M .1.4G rpool/ROOT/snv_98 25.1.29G 0 18K 0 6.4G rpool/swap 25.01M . and thus is counted in the snapshot's used property.1. By default. A snapshot's space referenced property value is the same as the file system's was when the snapshot was created. file systems. and volumes.29G 0 6.creation tank/home NAME CREATION tank/home@now Wed Jun 30 16:16 2010 tank/home/ahrens@now Wed Jun 30 16:16 2010 tank/home/anne@now Wed Jun 30 16:16 2010 tank/home/bob@now Wed Jun 30 16:16 2010 tank/home/cindys@now Wed Jun 30 16:16 2010
Disk Space Accounting for ZFS Snapshots
When a snapshot is created.50K tank/home/ahrens@wednesday 8.01M .4G rpool/export 25.29G 0 0 1.4G rpool/dump 25. deleting snapshots can increase the amount of disk space unique to (and thus used by) other snapshots. its disk space is initially shared between the snapshot and the file system. see Table 6–1.4G rpool/ROOT 25.79G 0 64K 0 7. and possibly with previous snapshots.4G rpool/export/home 25. You can identify additional information about how the values of the used property are consumed. the command cannot roll back to a snapshot other than the most recent snapshot. disk space that was previously shared becomes unique to the snapshot. Additionally. The file system reverts to its state at the time the snapshot was taken.Overview of ZFS Snapshots
pool/home/bob@monday 0 tank/home/ahrens@tuesday 8.00G 0 1.50K tank/home/ahrens@thursday 0 tank/home/cindys@today 8.00G 0 0 38K 0 20K 0 18K 18K 0 18K 0 0 512M 0 111M 401M 0
For a description of these properties.8G USED USEDSNAP USEDDS USEDREFRESERV USEDCHILD 7.780K .

the rollback fails.
Note – The file system that you want to roll back is unmounted and remounted.creation tank/home/ahrens NAME CREATION tank/home/ahrens@now Wed Jun 30 16:16 2010
Identifying ZFS Snapshot Differences (zfs diff)
You can determine ZFS snapshot differences by using the zfs diff command. If the file system cannot be unmounted. the tank/home/ahrens file system is rolled back to the tuesday snapshot:
# zfs rollback tank/home/ahrens@tuesday cannot rollback to ’tank/home/ahrens@tuesday’: more recent snapshots exist use ’-r’ to force deletion of the following snapshots: tank/home/ahrens@wednesday tank/home/ahrens@thursday # zfs rollback -r tank/home/ahrens@tuesday
In this example.
# zfs list -r -t snapshot -o name. The + indicates that fileB exists in the later snapshot. You can destroy earlier snapshots by specifying the -r option.Overview of ZFS Snapshots
To roll back to an earlier snapshot. For example. If clones of any intermediate snapshots exist. For example:
$ zfs diff tank/home/timh@1014 tank/home/timh@1015 M /tank/home/timh/ + /tank/home/timh/fileB
In the above output. the wednesday and thursday snapshots are destroyed because you rolled back to the earlier tuesday snapshot. all intermediate snapshots must be destroyed. The -f option forces the file system to be unmounted. the following two snapshots are created:
$ ls /tank/home/timh fileA $ zfs snapshot tank/home/timh@1014 $ ls /tank/home/timh fileA fileB $ zfs snapshot tank/home/timh@01015
Identify the snapshot differences. if it is currently
mounted.
Chapter 7 • Working With Oracle Solaris ZFS Snapshots and Clones 201
. the -R option must be specified to destroy the clones as well. if necessary. the M indicates that the directory has been modified. In the following example.

This tool provides the following features:
■ ■ ■ ■
SMF snapshot service instances that schedule reoccurring snapshots Automatic snapshots are scheduled from the zfssnap crontab Older snapshots are removed based on a predefined percentage of file system space used Browse and recover files from snapshots by using the GNOME file manager
You will need to add yourself to the zfssnap role to use the GNOME file manager to modify Time Slider behavior. keeping 31 snapshots snapshots every week. keeping 4 snapshots snapshots every hour.Overview of ZFS Snapshots
The following output indicates that a file in a snapshot has been renamed.
Managing Automatic ZFS Snapshots
The Time Slider snapshot tool automatically snapshots ZFS file systems and allows you to browse and recover snapshots of file systems. When the Time Slider tool is enabled. keeping 12 snapshots
Oracle Solaris ZFS Administration Guide • January 2011
. see zfs(1M).
$ mv /tank/cindys/fileB /tank/cindys/fileC $ zfs snapshot tank/cindys@0915 $ zfs diff tank/cindys@0914 tank/cindys@0915 M /tank/cindys/ R /tank/cindys/fileB -> /tank/cindys/fileC
The following table summarizes the file or directory changes that are identified by the zfs diff command. keeping 24 snapshots snapshots every day. ZFS file system snapshots are created based on the following criteria:
frequent hourly daily weekly monthly
202
snapshots every 15 mins. keeping 7 snapshots snapshots every month.
File or Directory Change Identifier
File or directory is modified or file or directory link changed File or directory is present in the older snapshot but not in the newer snapshot File or directory is present in the newer snapshot but not in the older snapshot File or directory is renamed
M — + R
For more information.

which is disabled by default. You can enable or disable these services from the command line or from the System->Preferences->Time Slider Setup menu.5K 0 46. For example:
# zfs set com. .Overview of ZFS Snapshots
▼ How to Manage Automatic ZFS Snapshots
1 2
Become an administrator. you can also customize which ZFS file systems to snapshot and adjust the file system capacity setting for when snapshots are removed.5K 0 46.sun:auto-snapshot=true rpool/ROOT/opensolaris
6
Choose to only take snapshots under a given schedule for a dataset and all direct descendent datasets from the command line.
# svcs | grep auto-snapshot online Oct_22 svc:/system/filesystem/zfs/auto-snapshot:frequent online Oct_22 svc:/system/filesystem/zfs/auto-snapshot:hourly online Oct_22 svc:/system/filesystem/zfs/auto-snapshot:weekly online Oct_22 svc:/system/filesystem/zfs/auto-snapshot:monthly online Oct_22 svc:/system/filesystem/zfs/auto-snapshot:daily
4
Confirm that automatic snapshots are created.sun:auto-snapshot=false rpool/export # zfs set com. For example:
# zfs set com.sun:auto-snapshot=false rpool # zfs set com. Enable the Time Slider service.sun:auto-snapshot:weekly=true rpool/export
Chapter 7 • Working With Oracle Solaris ZFS Snapshots and Clones 203
. From this menu.5K 0 46. .5K 0 18K 0 18K 0 18K 0 18K -
5
Disable or enable specific automatic snapshot services for the top-level dataset and all descendent datasets from the command line. USED AVAIL REFER MOUNTPOINT 0 46. For example:
# zfs list -t snapshot NAME rpool@zfs-auto-snap:weekly-2008-11-13-15:39 rpool@zfs-auto-snap:daily-2008-11-13-15:39 rpool@zfs-auto-snap:hourly-2008-11-13-15:39 rpool@zfs-auto-snap:frequent-2008-11-13-15:39 rpool/ROOT@zfs-auto-snap:weekly-2008-11-13-15:39 rpool/ROOT@zfs-auto-snap:daily-2008-11-13-15:39 rpool/ROOT@zfs-auto-snap:hourly-2008-11-13-15:39 rpool/ROOT@zfs-auto-snap:frequent-2008-11-13-15:39 .
3
Review the default automatic snapshot service instances that are started when the Time Slider service is enabled.

sun:auto-snapshot=false rpool/swap
9
Remove a range of unwanted snapshots.Overview of ZFS Snapshots
7
Change the frequency of a given snapshot schedule from the command line.File Browser
1
Browse your snapshots by opening any folder in the GNOME file manager. remove all automatic snapshots in the bash shell. For example:
# zfs set com. This column gives you contextual information about either of the following:
■ ■
The file version number. if any. do zfs destroy $s. which is accessed as follows:
■ ■
Click the Desktop icon under the Places tab Click the clock icon with the slider from the Desktop . Or. if necessary. Click on the clock icon to access snapshot navigation features. from the command line. Directly below the location: URL section is a one line description of the following information:
■ ■ ■
2
The timeline or date and time that the snapshot was taken The location in the backup timeline of the current snapshot The number of snapshots available for this directory and the space consumed by ZFS snapshots
3
Drag the slider into the past to retrieve previous versions of your files. For example. you can browse in list view mode (as oppose to icon view) so that a restore information column automatically appears. between the file snapshot and the latest version of the file
4
204
Recover files from an automatic snapshot from either of the following methods:
Oracle Solaris ZFS Administration Guide • January 2011
. If the Restore icon (clock with slider ) is enabled. from the command line.sun:auto-snapshot=false rpool/dump # zfs set com. You can open all your files in read-only mode. if necessary. as follows:
for s in ‘zfs list -H -o name -t snapshot | grep @zfs-auto-snap‘. done
▼ How to Recover Automatic ZFS Snapshots (GNOME File Manager)
You can browse and recover snapshots from the GNOME desktop file manager. if you browse in the current or latest version of a directory The difference. snapshots of this directory are available. For example:
# svccfg -s svc:/system/filesystem/zfs/auto-snapshot:frequent setprop zfs/period = 30 # svccfg -s svc:/system/filesystem/zfs/auto-snapshot:frequent refresh # svcadm restart svc:/system/filesystem/zfs/auto-snapshot:frequent
8
Disable automatic snapshot services for the swap and dump volumes.

As changes are made to the clone. a cloned workspace is created from the projects/newproject@today snapshot for a temporary user as projects/teamA/tempuser. When a snapshot is cloned. In addition. see “Setting ZFS Properties” on page 169. The new dataset is the same type (for example. copy and paste the selected snapshot to the present time. and the name of the new file system or volume. Use the zfs get and zfs set commands to view and change the properties of a cloned dataset. you can snapshot a clone. Even though the clone is created somewhere else in the dataset hierarchy. Then. You cannot create a clone of a file system in a pool that is different from where the original file system snapshot resides. Clones can only be created from a snapshot. it uses more disk space.Overview of ZFS Clones
■ ■
Drag and drop a snapshot into another file manager window Right click the mouse and select the restore to Desktop icon. The new file system or volume can be located anywhere in the ZFS hierarchy. if they exist. Because a clone initially shares all its disk space with the original snapshot. its used property value is initially zero. In the following example. creating a clone is nearly instantaneous and initially consumes no additional disk space.
■ ■ ■
“Creating a ZFS Clone” on page 205 “Destroying a ZFS Clone” on page 206 “Replacing a ZFS File System With a ZFS Clone” on page 206
Creating a ZFS Clone
To create a clone. As with snapshots. For more information about setting ZFS dataset properties. The used property of the original snapshot does not include the disk space consumed by the clone. specifying the snapshot from which to create the clone. Clones do not inherit the properties of the dataset from which it was created. Then. and the zfs destroy command lists any such dependencies. file system or volume) as the snapshot from which the clone was created. the original snapshot cannot be destroyed as long as the clone exists. an implicit dependency is created between the clone and snapshot.
Chapter 7 • Working With Oracle Solaris ZFS Snapshots and Clones 205
. use the zfs clone command. a new clone named tank/home/ahrens/bug123 with the same initial contents as the snapshot tank/ws/gate@yesterday is created:
# zfs snapshot tank/ws/gate@yesterday # zfs clone tank/ws/gate@yesterday tank/home/ahrens/bug123
In the following example. properties are set on the cloned workspace.
Overview of ZFS Clones
A clone is a writable volume or file system whose initial contents are the same as the dataset from which it was created. The origin property exposes this dependency.

Without clone promotion.
Replacing a ZFS File System With a ZFS Clone
You can use the zfs promote command to replace an active ZFS file system with a clone of that file system. For example:
# zfs destroy tank/home/ahrens/bug123
Clones must be destroyed before the parent snapshot can be destroyed. You can complete the clone replacement process by renaming the file systems. In the following example.2G 23K /tank/test tank/test/productA 104M 66. the tank/test/productA file system is cloned and then the clone file system. you cannot destroy an original file system of active clones.2G 104M /tank/test/productAbeta tank/test/productAbeta@today 0 .2G 104M /tank/test/productAbeta # zfs promote tank/test/productAbeta # zfs list -r tank/test NAME USED AVAIL REFER MOUNTPOINT tank/test 104M 66.
# zfs create tank/test # zfs create tank/test/productA # zfs snapshot tank/test/productA@today # zfs clone tank/test/productA@today tank/test/productAbeta # zfs list -r tank/test NAME USED AVAIL REFER MOUNTPOINT tank/test 104M 66. In addition.104M -
In this zfs list output.104M tank/test/productAbeta 0 66.2G 104M /tank/test/productA tank/test/productA@today 0 .Overview of ZFS Clones
# # # #
zfs zfs zfs zfs
snapshot projects/newproject@today clone projects/newproject@today projects/teamA/tempuser set sharenfs=on projects/teamA/tempuser set quota=5G projects/teamA/tempuser
Destroying a ZFS Clone
ZFS clones are destroyed by using the zfs destroy command. tank/test/productAbeta. see “Destroying a ZFS Clone” on page 206.2G 24K /tank/test tank/test/productA 0 66.2G 104M /tank/test/productA tank/test/productAbeta 104M 66. This feature enables you to clone and replace file systems so that the original file system becomes the clone of the specified file system. becomes the original tank/test/productA file system. note that the disk space accounting information for the original productA file system has been replaced with the productAbeta file system. this feature makes it possible to destroy the file system from which the clone was originally created. For example:
# zfs rename tank/test/productA tank/test/productAlegacy # zfs rename tank/test/productAbeta tank/test/productA # zfs list -r tank/test
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. For more information about destroying clones.

such as RAID-Z.
■ ■ ■ ■ ■ ■
“Saving ZFS Data With Other Backup Products” on page 208 “Sending a ZFS Snapshot” on page 208 “Receiving a ZFS Snapshot” on page 209 “Applying Different Property Values to a ZFS Snapshot Stream” on page 210 “Sending and Receiving Complex ZFS Snapshot Streams” on page 211 “Remote Replication of ZFS Data” on page 214
The following backup solutions for saving ZFS data are available:
■
Enterprise backup products – If you need the following features.
207
■
Chapter 7 • Working With Oracle Solaris ZFS Snapshots and Clones
. but with identical file system data. to restore a file or files from a previous version of a file system. You can redirect the output to a file or to a different system.
■
Saving snapshots – Use the zfs send and zfs receive commands to send and receive a ZFS snapshot. You can send ZFS snapshot data and receive ZFS snapshot data and file systems with these commands. If a full stream is received. You must restore the entire file system snapshot. see “Overview of ZFS Snapshots” on page 195. you could use this solution. The advantage of replicating a ZFS file system is that you can re-create a file system on a storage pool on another system.Sending and Receiving ZFS Data
Optionally. These commands do not provide a complete backup solution for saving your ZFS data. The zfs receive command creates a snapshot whose contents are specified in the stream that is provided on standard input. you can remove the legacy file system. For example. For more information about creating and rolling back to a snapshot. and specify different levels of configuration for the newly created pool. if necessary. By default. a new file system is created as well. For example:
# zfs destroy tank/test/productAlegacy
Sending and Receiving ZFS Data
The zfs send command creates a stream representation of a snapshot that is written to standard output. then consider an enterprise backup solution:
■ ■ ■
Per-file restoration Backup media verification Media management
■
File system snapshots and rolling back snapshots – Use the zfs snapshot and zfs rollback commands if you want to easily create a copy of a file system and revert to a previous file system version. a full stream is generated. You can save incremental changes between snapshots. but you cannot restore files individually. Remote replication – Use the zfs send and zfs receive commands to copy a file system from one system to another system. No special configuration or hardware is required. See the examples in the next section. This process is different from a traditional volume management product that might mirror devices across a WAN.

Check the appropriate options for both the tar and cpio commands. see the Oracle Solaris 11 Express Release Notes or the ZFS FAQ.
Saving ZFS Data With Other Backup Products
In addition to the zfs send and zfs receive commands. These utilities save and restore ZFS file attributes and ACLs. You can send incremental data by using the zfs send -i option. For up-to-date information about issues with ZFS and third-party backup products. which is assumed to be from the same file system as snap2. For example:
host1# zfs send tank/dana@snap1 | ssh host2 zfs recv newtank/dana
When you send a full stream. both tar and cpio translate NFSv4-style ACLs correctly. This shortcut means you only have to specify the name after the @ sign for snap1. use syntax similar to the following:
# zfs send tank/dana@snap1 | zfs recv spool/ds01
You can use zfs recv as an alias for the zfs receive command. In this case.Sending and Receiving ZFS Data
■
Archive utilities – Save ZFS data with archive utilities such as tar. you can also use archive utilities.org/bin/view/Community+Group+zfs/faq/#backupsoftware
Sending a ZFS Snapshot
You can use the zfs send command to send a copy of a snapshot stream and receive the snapshot stream in another pool on the same system or in another pool on a different system that is used to store backup data. If you are sending the snapshot stream to a different system. and pax or third-party backup products. For example:
host1# zfs send -i snap1 tank/dana@snap2 > ssh host2 zfs recv newtank/dana
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. the newtank/dana file system must already exist for the incremental receive to be successful.opensolaris. For example:
host1# zfs send -i tank/dana@snap1 tank/dana@snap2 | ssh host2 zfs recv newtank/dana
Note that the first argument (snap1) is the earlier snapshot and the second argument (snap2) is the later snapshot. Currently. available here: http://hub. cpio. The incremental snap1 source can be specified as the last component of the snapshot name. For example. to send the snapshot stream on a different pool to the same system. to save ZFS files. such as the tar and cpio commands. pipe the zfs send output through the ssh command. but pax does not. the destination file system must not exist.

consider compressing a ZFS snapshot stream representation with the gzip command. For example:
# zfs send pool/fs@snap | gzip > backupfile. The original file system to be received must not exist while it is being transferred.1
Then. you see a message similar to the following:
Chapter 7 • Working With Oracle Solaris ZFS Snapshots and Clones 209
. you must first roll back the receiving file system to receive the new incremental snapshot. you must first roll back the receiving file system. you can use zfs rename command to rename the file system.
For example:
# # # # zfs zfs zfs zfs send tank/gozer@0830 > /bkups/gozer.083006 rename tank/gozer tank/gozer. However. First.Sending and Receiving ZFS Data
This shortcut syntax is equivalent to the incremental syntax in the preceding example. the destination file system must already exist. For example:
host1# zfs send -i tank/dana@snap2 tank/dana@snap3 | ssh host2 zfs recv -F newtank/dana
When you receive an incremental snapshot.083006 receive tank/gozer2@today < /bkups/gozer. If the file system name already exists. make a change to the file system as follows:
host2# rm newtank/dana/file. The file system and all descendent file systems are unmounted. Or. The following message is displayed if you attempt to generate an incremental stream from a different file system snapshot1:
cannot send ’pool/fs@name’: not an earlier snapshot from the same fs
If you need to store many copies.gz
Receiving a ZFS Snapshot
Keep the following key points in mind when you receive a file system snapshot:
■ ■ ■ ■ ■
Both the snapshot and the file system are received. If you make changes to the file system and you do not roll back the receiving file system to receive the new incremental snapshot or you do not use the -F option. Consider the following example.old rename tank/gozer2 tank/gozer
If you make a change to the destination file system and you want to perform another incremental send of a snapshot. perform an incremental send of tank/dana@snap3. you can eliminate the rollback step by using the -F option. The file systems are inaccessible while they are being received.

If you accidentally provide the name of different file system that doesn't match the incremental source specified in the zfs receive command. For example. so for bpool/data.Sending and Receiving ZFS Data
host1# zfs send -i tank/dana@snap4 tank/dana@snap5 | ssh host2 zfs recv newtank/dana cannot receive: destination has been modified since most recent snapshot
The following checks are performed before the -F option is successful:
■
If the most recent snapshot doesn't match the incremental source. you can also disable a file system property when the snapshot stream is received. neither the rollback nor the receive is completed. but you can specify a different local property value when the snapshot stream is received. such as a mountpoint property value. restorepool. In some cases.
# zfs get compression tank/data NAME PROPERTY VALUE SOURCE tank/data compression off default # zfs snapshot tank/data@snap1 # zfs send -p tank/data@snap1 | zfs recv -o compression=on -d bpool # zfs get -o all compression bpool/data NAME PROPERTY VALUE RECEIVED SOURCE bpool/data compression on off local
In the above example. you might want to keep all the original snapshot properties. In addition. for recovery purposes. Or. and the following error message is returned:
cannot send ’pool/fs@name’: not an earlier snapshot from the same fs
■
Applying Different Property Values to a ZFS Snapshot Stream
You can send a ZFS snapshot stream with a certain file system property. the compression property is enabled when the snapshot was received into the bpool. file system properties in a send stream might not apply to the receiving file system or the local file system properties might interfere with a restore. the compression value is on. and an error message is returned. In this case. neither the roll back nor the receive is completed. the tank/data file system has the compression property is disabled. you can specify that the original property value is used when the snapshot stream is received to recreate the original file system. A snapshot of the tank/data file system is sent with properties (-p) to a backup pool and is received with the compression property enabled. If this snapshot stream is sent to a new pool. For example:
# zfs send -b bpool/data@snap1 | zfs recv -d restorepool # zfs get -o all compression restorepool/data
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. you would use the zfs send -b option to restore the original snapshot properties.

descendent file systems.
# zfs send -R tank/home@1020 | zfs recv # zfs get -r quota bpool/home NAME PROPERTY VALUE bpool/home quota none bpool/home@1020 quota bpool/home/cindys quota none bpool/home/cindys@1020 quota bpool/home/tom quota none bpool/home/tom@1020 quota -x quota bpool/home SOURCE default local local -
If the recursive snapshot was not received with the -x option. The original snapshot must already exist on the receiving side to accept the incremental stream. If you have a local file system property value in a snapshot stream and you want to disable the property when it is received. use the zfs receive -x command. but without the quota property values. Or. send a recursive snapshot stream of home directory file systems with all file system properties reserved to a backup pool. When the replication stream is received. and clones are preserved. For example. the quota property would be set in the received file systems. all properties. the compression value is off.
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. Use the zfs send -R option to send a replication stream of all descendent file systems. use this option to send an incremental stream from the original snapshot to create a clone. which represents the snapshot compression value from the original tank/data file system.Sending and Receiving ZFS Data
NAME PROPERTY VALUE restorepool/data compression off
RECEIVED SOURCE off received
In the above example.
# zfs send -R tank/home@1020 | zfs # zfs get -r quota bpool/home NAME PROPERTY bpool/home quota bpool/home@1020 quota bpool/home/cindys quota bpool/home/cindys@1020 quota bpool/home/tom quota bpool/home/tom@1020 quota recv bpool/home VALUE none 2G 4G SOURCE default received received -
Sending and Receiving Complex ZFS Snapshot Streams
This section describes how to use the zfs send -I and -R options to send and receive more complex snapshot streams. Keep the following points in mind when sending and receiving complex ZFS snapshot streams:
■
Use the zfs send -I option to send all incremental streams from one snapshot to a cumulative snapshot. snapshots.

# zfs destroy pool/fs@snapB # zfs destroy pool/fs@snapC # zfs destroy pool/fs@snapD
To receive the combined snapshot. But. only snapD (for all descendents) are sent.5K pool/fs@snapD 0 21K
MOUNTPOINT /pool /pool/fs -
You can also use the zfs send -I command to combine a snapshot and a clone snapshot to create a combined dataset. you can access streams from older pool versions by using a newer software version.18.5G 20K pool/fs 71K 16. The zfs recv -F syntax in this case also retains its rollback if necessary meaning. all snapshots between snapA and snapD are sent. the receiving system must be running a software version capable of sending them. you would remove snapB. For example. dataset destroy operations are ignored. if -I is used. If zfs recv -F is not specified when receiving the replication stream. snapC. However. you must be running recent software to receive a stream sent with the newer options. you can send and receive streams created with the newer options to and from a version 3 pool.
EXAMPLE 7–1
Sending and Receiving Complex ZFS Snapshot Streams
A group of incremental snapshots can be combined into one snapshot by using the zfs send -I option.
■
Changes to properties are preserved. For example:
# zfs send -I pool/fs@snapA pool/fs@snapD > /snaps/fs@all-I
Then.5K pool/fs@snapB 17K 20K pool/fs@snapC 17K .5G 21K pool/fs@snapA 16K . and snapD.Sending and Receiving ZFS Data
■
Use both options to send an incremental replication stream.
# zfs receive -d -F pool/fs < /snaps/fs@all-I # zfs list NAME USED AVAIL REFER pool 428K 16. As with other (non zfs send -R) -i or -I cases.20. you would use the following command.
■
■
■
To receive any of these new types of zfs send streams. For example:
# # # # #
212
zfs zfs zfs zfs zfs
create pool/fs snapshot pool/fs@snap1 clone pool/fs@snap1 pool/clone snapshot pool/clone@snapA send -I pool/fs@snap1 pool/clone@snapA > /snaps/fsclonesnap-I
Oracle Solaris ZFS Administration Guide • January 2011
. as are snapshot and file system rename and destroy operations are preserved. If -i is used. The stream version is incremented.

Remote Replication of ZFS Data
You can use the zfs send and zfs recv commands to remotely copy a snapshot stream representation from one system to another system. For example:
# zfs send tank/cindy@today | ssh newsys zfs recv sandbox/restfs@today

This command sends the tank/cindy@today snapshot data and receives it into the sandbox/restfs file system. The command also creates a restfs@today snapshot on the newsys system. In this example, the user has been configured to use ssh on the remote system.

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C H A P T E R

Using ACLs and Attributes to Protect Oracle Solaris ZFS Files

8

8

This chapter provides information about using access control lists (ACLs) to protect your ZFS files by providing more granular permissions than the standard UNIX permissions. The following sections are provided in this chapter:
■ ■ ■ ■ ■

New Solaris ACL Model
Previous versions of Solaris supported an ACL implementation that was primarily based on the POSIX-draft ACL specification. The POSIX-draft based ACLs are used to protect UFS files and are translated by versions of NFS prior to NFSv4. With the introduction of NFSv4, a new ACL model fully supports the interoperability that NFSv4 offers between UNIX and non-UNIX clients. The new ACL implementation, as defined in the NFSv4 specification, provides much richer semantics that are based on NT-style ACLs. The main differences of the new ACL model are as follows:
■ ■ ■

Based on the NFSv4 specification and similar to NT-style ACLs. Provide much more granular set of access privileges. For more information, see Table 8–2. Set and displayed with the chmod and ls commands rather than the setfacl and getfacl commands. Provide richer inheritance semantics for designating how access privileges are applied from directory to subdirectories, and so on. For more information, see “ACL Inheritance” on page 220.
215

■

New Solaris ACL Model

Both ACL models provide more fine-grained access control than is available with the standard file permissions. Much like POSIX-draft ACLs, the new ACLs are composed of multiple Access Control Entries (ACEs). POSIX-draft style ACLs use a single entry to define what permissions are allowed and what permissions are denied. The new ACL model has two types of ACEs that affect access checking: ALLOW and DENY. As such, you cannot infer from any single ACE that defines a set of permissions whether or not the permissions that weren't defined in that ACE are allowed or denied. Translation between NFSv4-style ACLs and POSIX-draft ACLs is as follows:
■

If you use any ACL-aware utility, such as the cp, mv, tar, cpio, or rcp commands, to transfer UFS files with ACLs to a ZFS file system, the POSIX-draft ACLs are translated into the equivalent NFSv4-style ACLs. Some NFSv4-style ACLs are translated to POSIX-draft ACLs. You see a message similar to the following if an NFSv4–style ACL isn't translated to a POSIX-draft ACL:
# cp -p filea /var/tmp cp: failed to set acl entries on /var/tmp/filea

■

■

If you create a UFS tar or cpio archive with the preserve ACL option (tar -p or cpio -P) on a system that runs a current Solaris release, you will lose the ACLs when the archive is extracted on a system that runs a previous Solaris release. All of the files are extracted with the correct file modes, but the ACL entries are ignored. You can use the ufsrestore command to restore data into a ZFS file system. If the original data includes POSIX-style ACLs, they are converted to NFSv4-style ACLs. If you attempt to set an NFSv4-style ACL on a UFS file, you see a message similar to the following:
chmod: ERROR: ACL type’s are different

■

■

■

If you attempt to set a POSIX-style ACL on a ZFS file, you will see messages similar to the following:
# getfacl filea File system doesn’t support aclent_t style ACL’s. See acl(5) for more information on Solaris ACL support.

For information about other limitations with ACLs and backup products, see “Saving ZFS Data With Other Backup Products” on page 208.

chmod [options] A-owner@, group@, everyone@:access-permissions/...[:inheritance-flags]:deny | allow file ... chmod [options] A[index]- file Syntax for Setting Non-Trivial ACLs chmod [options] A[index]{+|=}user|group:name:access-permissions/...[:inheritance-flags]:deny | allow file chmod [options] A-user|group:name:access-permissions/...[:inheritance-flags]:deny | allow file ... chmod [options] A[index]- file owner@, group@, everyone@ Identifies the ACL-entry-type for trivial ACL syntax. For a description of ACL-entry-types, see Table 8–1. user or group:ACL-entry-ID=username or groupname Identifies the ACL-entry-type for explicit ACL syntax. The user and group ACL-entry-type must also contain the ACL-entry-ID, username or groupname. For a description of ACL-entry-types, see Table 8–1. access-permissions/.../ Identifies the access permissions that are granted or denied. For a description of ACL access privileges, see Table 8–2. inheritance-flags Identifies an optional list of ACL inheritance flags. For a description of the ACL inheritance flags, see Table 8–3. deny | allow Identifies whether the access permissions are granted or denied. In the following example, the ACL-entry-ID value is not relevant.
group@:write_data/append_data/execute:deny

The following example includes an ACL-entry-ID because a specific user (ACL-entry-type) is included in the ACL.
0:user:gozer:list_directory/read_data/execute:allow

When an ACL entry is displayed, it looks similar to the following:
2:group@:write_data/append_data/execute:deny

The 2 or the index-ID designation in this example identifies the ACL entry in the larger ACL, which might have multiple entries for owner, specific UIDs, group, and everyone. You can
Chapter 8 • Using ACLs and Attributes to Protect Oracle Solaris ZFS Files 217

New Solaris ACL Model

specify the index-ID with the chmod command to identify which part of the ACL you want to modify. For example, you can identify index ID 3 as A3 to the chmod command, similar to the following:
chmod A3=user:venkman:read_acl:allow filename

ACL entry types, which are the ACL representations of owner, group, and other, are described in the following table.
TABLE 8–1

ACL Entry Types
Description

ACL Entry Type

owner@ group@ everyone@

Specifies the access granted to the owner of the object. Specifies the access granted to the owning group of the object. Specifies the access granted to any user or group that does not match any other ACL entry. With a user name, specifies the access granted to an additional user of the object. Must include the ACL-entry-ID, which contains a username or userID. If the value is not a valid numeric UID or username, the ACL entry type is invalid. With a group name, specifies the access granted to an additional group of the object. Must include the ACL-entry-ID, which contains a groupname or groupID. If the value is not a valid numeric GID or groupname, the ACL entry type is invalid.

Permission to add a new file to a directory. On a directory, permission to create a subdirectory. Placeholder. Not currently implemented. Permission to delete a file. Permission to delete a file or directory within a directory. Permission to execute a file or search the contents of a directory. Permission to list the contents of a directory. Permission to read the ACL (ls).

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TABLE 8–2

ACL Access Privileges
Compact Access Privilege

(Continued)
Description

Access Privilege

read_attributes

a

Permission to read basic attributes (non-ACLs) of a file. Think of basic attributes as the stat level attributes. Allowing this access mask bit means the entity can execute ls(1) and stat(2). Permission to read the contents of the file. Permission to read the extended attributes of a file or perform a lookup in the file's extended attributes directory. Placeholder. Not currently implemented. Permission to create extended attributes or write to the extended attributes directory. Granting this permission to a user means that the user can create an extended attribute directory for a file. The attribute file's permissions control the user's access to the attribute.

read_data read_xattr synchronize write_xattr

r R s W

write_data write_attributes write_acl write_owner

w A C o

Permission to modify or replace the contents of a file. Permission to change the times associated with a file or directory to an arbitrary value. Permission to write the ACL or the ability to modify the ACL by using the chmod command. Permission to change the file's owner or group. Or, the ability to execute the chown or chgrp commands on the file. Permission to take ownership of a file or permission to change the group ownership of the file to a group of which the user is a member. If you want to change the file or group ownership to an arbitrary user or group, then the PRIV_FILE_CHOWN privilege is required.

ZFS ACL Sets
The following ACL combinations can be applied in an ACL set rather than setting individual permissions separately. The following ACL sets are available.
ACL Set Name Included ACL Permissions

full_set modify_set read_set

All permissions all permissions except write_acl and write_owner read_data, read_attributes, read_xattr, and read_acl

and write_xattr
These ACL sets are prefined and cannot be modified. to indicate what to inherit. the dir_inherit flag. ACLs are not propagated. Only inherit the ACL from the parent directory to the first-level contents of the directory. the dir_inherit flag. the following flags are only applicable to a SMB client or server. to indicate what to inherit. append_data. or both.
dir_inherit
d
inherit_only
i
no_propagate
n
-
N/A
Currently.
ACL Inheritance
The purpose of using ACL inheritance is so that a newly created file or directory can inherit the ACLs they are intended to inherit. write_attributes. No permission granted. The optional inheritance flags are described in the following table. not the second-level or subsequent contents. By default. Inherit the ACL from the parent directory but applies only to newly created files or subdirectories and not the directory itself. If you set a non-trivial ACL on a directory. but without disregarding the existing permission bits on the parent directory. successful_access S Indicates whether an alarm or audit record should be initiated upon a successful access. it is not inherited to any subsequent directory. This flag requires the file_inherit flag.
TABLE 8–3
ACL Inheritance Flags
Compact Inheritance Flag Description
Inheritance Flag
file_inherit
f
Only inherit the ACL from the parent directory to the directory's files. You must specify the inheritance of an ACL on a file or directory.
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. Only inherit the ACL from the parent directory to the directory's subdirectories. This flag requires the file_inherit flag. or both.New Solaris ACL Model
ACL Set Name
Included ACL Permissions
write_set
write_data. This flag is used with audit or alarm ACE types.

the write_owner and write_acl permissions are removed when an ACL entry is inherited. see the next section.Setting ACLs on ZFS Files
TABLE 8–3
ACL Inheritance Flags
(Continued)
Description
Inheritance Flag
Compact Inheritance Flag
failed_access
F
Indicates whether an alarm or audit record should be initiated when an access fails. In addition. except that when passthrough-x is enabled. ZFS files still have permission bits and a mode. Typically.
Setting ACLs on ZFS Files
As implemented with ZFS. If no inheritable ACEs exist that affect the mode.
■
■
■
■
The default mode for the aclinherit is restricted. noallow – For new objects. As such. if you remove a non-trivial ACL that granted a user access to a file or
Chapter 8 • Using ACLs and Attributes to Protect Oracle Solaris ZFS Files 221
. the file's ACL is updated accordingly. Indicates that an ACE was inherited. if you change the permissions of the file.
inherited
I
In addition. passthrough-x – Has the same semantics as passthrough. files are created with the execute (x) permission. For more information. the ACL is trivial in that it only represents the traditional UNIX owner/group/other entries. passthrough – When property value is set to passthrough. only inheritable ACL entries that have an access type of deny are inherited. The ACL on the file or directory is equal to the permission mode of the file or directory. you can set a default ACL inheritance policy on the file system that is more strict or less strict by using the aclinherit file system property. ZFS provides a pure ACL model. ACLs are composed of an array of ACL entries. but these values are more of a cache of what the ACL represents. where all files have an ACL. Values include the following:
■
discard – For new objects. but only if execute permission is set in the file creation mode and in an inheritable ACE that affects the mode. then the mode is set in accordance to the requested mode from the application. no ACL entries are inherited when a file or directory is created. restricted – For new objects.
ACL Property (aclinherit)
The ZFS file system includes the aclinherit property to determine the behavior of ACL inheritance. files are created with a mode determined by the inheritable ACEs. This flag is used with audit or alarm ACE types.

The primary rules of ACL access on a ZFS file are as follows:
■ ■ ■
ZFS processes ACL entries in the order they are listed in the ACL. from the top down. extended attributes.1 root root 206674 Jun 14 14:48 /tank/file. any permission left unspecified is denied. The owner of the file is granted the write_acl permission unconditionally. everyone@) has an ACL entry in this example. A description of this file ACL is as follows: 0:owner@ The owner can read and modify the contents of the file (read_data/write_data/append_data/read_xattr).Setting ACLs on ZFS Files
directory. All access control decisions are governed by the permissions represented in a file or directory's ACL. group@. you have to use the ACL inheritance flags.1 -rw-r--r-. the owner can modify the ownership of the file (write_owner:allow). When you create a new file and depending on the umask value. In addition. similar to the following. the ACL is not automatically inherited by the directory's children. see Table 8–3 and “Setting ACL Inheritance on ZFS Files in Verbose Format” on page 228.
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. and ACLs (write_xattr/read_attributes/write_attributes/ read_acl/write_acl). even if the permission is explicitly denied. it cannot be denied by a subsequent ACL deny entry in the same ACL permission set. the privilege subsystem determines what access request is granted for the owner of the file or for superuser. In the cases of deny permissions or when an access permission is missing. The owner can also modify the file's attributes such as timestamps. If you set an non-trivial ACL and you want it inherited to the directory's children. Only ACL entries that have a “who” that matches the requester of the access are processed. is applied:
$ ls -v file. For more information.
■
If you set a non-trivial ACL on a directory. The synchronize access permission is not currently implemented. a default trivial ACL.1 0:owner@:read_data/write_data/append_data/read_xattr/write_xattr /read_attributes/write_attributes/read_acl/write_acl/write_owner /synchronize:allow 1:group@:read_data/read_xattr/read_attributes/read_acl/synchronize:allow 2:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize :allow
Each user category (owner@. Once an allow permission has been granted. that user could still have access to the file or directory because of the file or directory's permission bits that grant access to group or everyone. Otherwise. This mechanism prevents owners of files from getting locked out of their files and enables superuser to modify files for recovery purposes.

1 drwxr-xr-x 2 root root 2 Jun 14 14:58 dir. and ACLs (/read_xattr/write_xattr/read_attributes/write_attributes/read_acl/ write_acl). a default directory ACL is similar to the following:
$ ls -dv dir. The synchronize access permission is not currently implemented.1 0:owner@:list_directory/read_data/add_file/write_data/add_subdirectory /append_data/read_xattr/write_xattr/execute/read_attributes /write_attributes/read_acl/write_acl/write_owner/synchronize:allow 1:group@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow 2:everyone@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow
A description of this directory ACL is as follows: 0:owner@ The owner can read and modify the directory contents (list_directory/read_data/add_file/write_data/add_subdirectory /append_data). the owner can modify the ownership of the directory (write_owner:allow).
2:everyone@
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. the group has execute permission to search the directory contents (list_directory/read_data/read_xattr/execute/read_attributes /read_acl). 1:group@ The group can list and read the directory contents and the directory's attributes. search the contents (execute). Everyone who is not user or group is granted read and execute permissions to the directory contents and the directory's attributes (list_directory/read_data/read_xattr/execute/read_ attributes/read_acl:allow). In addition. In addition.
When a new directory is created and depending on the umask value. and read and modify the file's attributes such as timestamps.Setting ACLs on ZFS Files
1:group@ 2:everyone@
The group is granted read permissions to the file and the file's attributes (read_data/read_xattr/read_attributes/read_acl:allow). extended attributes. Everyone who is not user or group is granted read permissions to the file and the file's attributes (read_data/read_xattr/read_attributes/read_acl/:allow).

the file permissions are computed to be 000 because no ACL entries exist for owner@. two non-trivial ACEs exist on test5.dir.3 0:owner@:execute:deny 1:owner@:read_data/write_data/append_data/read_xattr/write_xattr /read_attributes/write_attributes/read_acl/write_acl/write_owner /synchronize:allow 2:group@:read_data/read_xattr/execute/read_attributes/read_acl /synchronize:allow 3:everyone@:read_data/read_xattr/execute/read_attributes/read_acl /synchronize:allow
EXAMPLE 8–4
Restoring Trivial ACLs on ZFS Files
You can use the chmod command to remove all non-trivial ACLs on a file or directory.3 # ls -v file. the permission bits are set to 666. or everyone@.3 # ls -v file.3 0:user:gozer:read_data:allow
In this output.Setting and Displaying ACLs on ZFS Files in Verbose Format
EXAMPLE 8–3
ACL Interaction With Permissions on ZFS Files
(Continued)
In this output. In this model. In the following example.3 ----------+ 1 root root 2380 Jun 15 10:17 file. group.
# ls -dv test5. everyone@ specifies access to any user or group.dir drwxr-xr-x+ 2 root root 2 Jun 15 10:24 test5. group@.3 -rw-r-xr-x 1 root root 2380 Jun 15 10:17 file. The owner of the file can resolve this problem by resetting the permissions (and the ACL) as follows:
# chmod 655 file. the chmod syntax effectively replaces the existing ACL with read_data/write_data:allow permissions to read/write permissions for owner. the existing ACL is replaced with read permissions for user gozer. which represent the traditional permission components of a file.dir 0:user:lp:read_data:file_inherit:deny 1:user:gozer:read_data:file_inherit:deny 2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory /append_data/read_xattr/write_xattr/execute/read_attributes /write_attributes/read_acl/write_acl/write_owner/synchronize:allow 3:group@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow 4:everyone@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow
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. and everyone@.
# chmod A=user:gozer:read_data:allow file. In the following example. Since no owner@ or group@ ACL entry exists to override the permissions for owner and group.

Setting and Displaying ACLs on ZFS Files in Verbose Format
EXAMPLE 8–4
Restoring Trivial ACLs on ZFS Files
(Continued)
In the following example.1 # ls -v file.2 0:user:otto:read_data/write_data/append_data/read_xattr/write_xattr /read_attributes/write_attributes/read_acl:allow 1:owner@:read_data/write_data/append_data/read_xattr/write_xattr /read_attributes/write_attributes/read_acl/write_acl/write_owner /synchronize:allow 2:group@:read_data/read_xattr/read_attributes/read_acl/synchronize:allow
Setting ACL Inheritance on ZFS Files in Verbose Format
You can determine how ACLs are inherited or not inherited on files and directories. For example.dir drwxr-xr-x 2 root root 2 Jun 15 10:24 test5. By default. the non-trivial ACLs for users gozer and lp are removed.2 # ls -v file. You must specify the inheritance of an ACL on a file or directory. you can apply the write_set as follows:
# chmod A+user:otto:read_set:allow file.1 0:user:otto:read_data/read_xattr/read_attributes/read_acl:allow 1:owner@:read_data/read_xattr/write_xattr/read_attributes /write_attributes/read_acl/write_acl/write_owner/synchronize:allow 2:group@:read_data/read_xattr/read_attributes/read_acl/synchronize:allow 3:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize:allow
You can apply the write_set and read_set as follows:
# chmod A+user:otto:read_set/write_set:allow file. see “ZFS ACL Sets” on page 219.1 -r--r--r--+ 1 root root 206674 Jun 15 10:34 file.test5. The remaining ACL contains the default values for owner@. and everyone@.
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. group@. If you set a non-trivial ACL on a directory.dir 0:owner@:list_directory/read_data/add_file/write_data/add_subdirectory /append_data/read_xattr/write_xattr/execute/read_attributes /write_attributes/read_acl/write_acl/write_owner/synchronize:allow 1:group@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow 2:everyone@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow
EXAMPLE 8–5
Applying an ACL Set to ZFS Files
ACL sets are available so that you do not have to apply ACL permissions separately.2 -rw-r-----+ 1 root root 28092 Jun 15 10:08 file. ACLs are not propagated. For a description of ACL sets. the ACL is not inherited by any subsequent directory.
# chmod A.dir # ls -dv test5.

User gozer would only have access to sub.
# chmod A+user:gozer:read_data/write_data/execute:allow test.dir/sub.dir # ls -dv test. see “ACL Inheritance” on page 220.dir # ls -dv test2.dir 0:user:gozer:list_directory/read_data/add_file/write_data/execute:allow 1:owner@:list_directory/read_data/add_file/write_data/add_subdirectory /append_data/read_xattr/write_xattr/execute/read_attributes /write_attributes/read_acl/write_acl/write_owner/synchronize:allow 2:group@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow 3:everyone@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow
If a test. For more information. a non-trivial ACE of read_data/write_data/execute is applied for user gozer on test.dir if the permissions on sub.. In the following example. By default. or everyone@.Setting and Displaying ACLs on ZFS Files in Verbose Format
The aclinherit property can be set globally on a file system. the ACE for user gozer is not propagated. In the following example. aclinherit is set to restricted.dir drwxr-xr-x 2 root root 2 Jun 15 10:41 test.dir 0:user:gozer:read_data/write_data:file_inherit:allow 1:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
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.dir directory for user gozer so that he has read access on any newly created files.dir # ls -dv test.
EXAMPLE 8–6
Granting Default ACL Inheritance
By default.dir/sub. group member.dir drwxr-xr-x+ 2 root root 2 Jun 15 10:42 test2.dir subdirectory is created. ACLs are not propagated through a directory structure.dir granted him access as the file owner.dir.dir 0:owner@:list_directory/read_data/add_file/write_data/add_subdirectory /append_data/read_xattr/write_xattr/execute/read_attributes /write_attributes/read_acl/write_acl/write_owner/synchronize:allow 1:group@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow 2:everyone@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow
EXAMPLE 8–7
Granting ACL Inheritance on Files and Directories
This series of examples identify the file and directory ACEs that are applied when the file_inherit flag is set.
# chmod A+user:gozer:read_data/write_data:file_inherit:allow test2. read_data/write_data permissions are added for files in the test.dir/sub.
# mkdir test.dir drwxr-xr-x+ 2 root root 2 Jun 15 10:40 test.

dir/file. is used to propagate the ACL through the directory structure.dir/file. user gozer is granted read.Setting and Displaying ACLs on ZFS Files in Verbose Format
EXAMPLE 8–7
Granting ACL Inheritance on Files and Directories
(Continued)
/append_data/read_xattr/write_xattr/execute/read_attributes /write_attributes/read_acl/write_acl/write_owner/synchronize:allow 2:group@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow 3:everyone@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow
In the following example.2 0:user:gozer:read_data:inherited:allow 1:owner@:read_data/write_data/append_data/read_xattr/write_xattr /read_attributes/write_attributes/read_acl/write_acl/write_owner /synchronize:allow 2:group@:read_data/read_xattr/read_attributes/read_acl/synchronize:allow 3:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize :allow
Because the aclinherit property for this file system is set to the default mode.2 0:user:gozer:list_directory/read_data/add_file/write_data:file_inherit /inherit_only/inherited:allow 1:owner@:list_directory/read_data/add_file/write_data/add_subdirectory /append_data/read_xattr/write_xattr/execute/read_attributes /write_attributes/read_acl/write_acl/write_owner/synchronize:allow 2:group@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow 3:everyone@:list_directory/read_data/read_xattr/execute/read_attributes /read_acl/synchronize:allow
The following series of examples identify the file and directory ACLs that are applied when both the file_inherit and dir_inherit flags are set.2 # ls -dv test2. user gozer does not have write_data permission on file.dir/subdir.dir/subdir. user gozer is only granted or denied permission from everyone@ permissions unless he is the file owner or is a member of the file's group owner. restricted.2 -rw-r--r--+ 1 root root 0 Jun 15 10:43 test2.dir/subdir.2 # ls -v test2. which is applied when the file_inherit or dir_inherit flags are set. means user gozer can read the contents of any newly created file.2 file.dir/file. Note the inherit_only permission.2 drwxr-xr-x+ 2 root root 2 Jun 15 10:48 test2.2 because the group permission of the file does not allow it.
# touch test2. write. read_data:file_inherit:allow.dir/file.
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. and execute permissions that are inherited for newly created files and directories. For example:
# mkdir test2. The ACL inheritance granted. In the following example. As such. user gozer's permissions are applied on the newly created test2.

In these examples, because the permission bits of the parent directory for group@ and everyone@ deny write and execute permissions, user gozer is denied write and execute permissions. The default aclinherit property is restricted, which means that write_data and execute permissions are not inherited. In the following example, user gozer is granted read, write, and execute permissions that are inherited for newly created files, but are not propagated to subsequent contents of the directory.
# chmod A+user:gozer:read_data/write_data/execute:file_inherit/no_propagate:allow test4.dir

In the following example, two non-trivial ACLs with file inheritance are set. One ACL allows read_data permission, and one ACL denies read_data permission. This example also illustrates how you can specify two ACEs in the same chmod command.
# zfs set aclinherit=noallow tank/cindys # chmod A+user:gozer:read_data:file_inherit:deny,user:lp:read_data:file_inherit:allow test6.dir

Setting and Displaying ACLs on ZFS Files in Compact Format
You can set and display permissions on ZFS files in a compact format that uses 14 unique letters to represent the permissions. The letters that represent the compact permissions are listed in Table 8–2 and Table 8–3. You can display compact ACL listings for files and directories by using the ls -V command. For example:
# ls -V file.1 -rw-r--r-- 1 root root 206674 Jun 15 10:34 file.1 owner@:rw-p--aARWcCos:-------:allow group@:r-----a-R-c--s:-------:allow everyone@:r-----a-R-c--s:-------:allow

The compact ACL output is described as follows: owner@ The owner can read and modify the contents of the file (rw=read_data/write_data), (p=append_data). The owner can also modify the file's attributes such as timestamps, extended attributes, and ACLs

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Setting and Displaying ACLs on ZFS Files in Compact Format

(a=read_attributes, A=write_xattr, R=read_xattr, W=write_attributes, c=read_acl, C=write_acl). In addition, the owner can modify the ownership of the file (o=write_owner). The synchronize access permission is not currently implemented. group@ The group is granted read permissions to the file (r=read_data) and the file's attributes (a=read_attributes, R=read_xattr, c=read_acl). The synchronize access permission is not currently implemented. everyone@ Everyone who is not user or group is granted read permissions to the file and the file's attributes (r=read_data, a=append_data, R=read_xattr, c=read_acl, and s=synchronize). The synchronize access permission is not currently implemented. Compact ACL format provides the following advantages over verbose ACL format:
■ ■

Permissions can be specified as positional arguments to the chmod command. The hyphen (-) characters, which identify no permissions, can be removed and only the required letters need to be specified. Both permissions and inheritance flags are set in the same fashion.

■

For information about using the verbose ACL format, see “Setting and Displaying ACLs on ZFS Files in Verbose Format” on page 224.
EXAMPLE 8–11

A file system that has the aclinherit property set to passthrough inherits all inheritable ACL entries without any modifications made to the ACL entries when they are inherited. When this property is set to passthrough, files are created with a permission mode that is determined by the inheritable ACEs. If no inheritable ACEs exist that affect the permission mode, then the permission mode is set in accordance to the requested mode from the application. The following examples use compact ACL syntax to show how to inherit permission bits by setting aclinherit mode to passthrough. In this example, an ACL is set on test1.dir to force inheritance. The syntax creates an owner@, group@, and everyone@ ACL entry for newly created files. Newly created directories inherit an @owner, group@, and everyone@ ACL entry.
# zfs set aclinherit=passthrough tank/cindys # pwd /tank/cindys # mkdir test1.dir # chmod A=owner@:rwxpcCosRrWaAdD:fd:allow,group@:rwxp:fd:allow,everyone@::fd:allow test1.dir # ls -Vd test1.dir drwxrwx---+ 2 root root 2 Jun 15 13:17 test1.dir owner@:rwxpdDaARWcCos:fd-----:allow group@:rwxp----------:fd-----:allow everyone@:--------------:fd-----:allow

In this example, a newly created directory inherits both ACEs that control access to this directory as well as ACEs for future propagation to children of the newly created directory.
# mkdir subdir.1 # ls -dV subdir.1 drwxrwx---+ 2 root root 2 Jun 15 13:20 subdir.1 owner@:rwxpdDaARWcCos:fd----I:allow group@:rwxp----------:fd----I:allow everyone@:--------------:fd----I:allow

The fd---- entries are for propagating inheritance and are not considered during access control. In this example, a file is created with a trivial ACL in another directory where inherited ACEs are not present.
# cd /tank/cindys # mkdir test2.dir # cd test2.dir # touch file.2 # ls -V file.2 -rw-r--r-- 1 root root 0 Jun 15 13:21 file.2 owner@:rw-p--aARWcCos:-------:allow group@:r-----a-R-c--s:-------:allow everyone@:r-----a-R-c--s:-------:allow
EXAMPLE 8–13

ACL Inheritance With ACL Inherit Mode Set to Pass Through-X

When aclinherit=passthrough-x is enabled, files are created with the execute (x) permission for owner@, group@, or everyone@, but only if execute permission is set in the file creation mode and in an inheritable ACE that affects the mode. The following example shows how to inherit the execute permission by setting aclinherit mode to passthrough-x.
# zfs set aclinherit=passthrough-x tank/cindys

The following ACL is set on /tank/cindys/test1.dir to provide executable ACL inheritance for files for owner@.

Two types of delegated permissions are supported:
■
Individual permissions can be explicitly delegated such as create. The following sections are provided in this chapter:
■ ■ ■ ■ ■
“Overview of ZFS Delegated Administration” on page 241 “Delegating ZFS Permissions” on page 242 “Displaying ZFS Delegated Permissions (Examples)” on page 249 “Delegating ZFS Permissions (Examples)” on page 246 “Removing ZFS Delegated Permissions (Examples)” on page 251
Overview of ZFS Delegated Administration
ZFS delegated administration enables you to distribute refined permissions to specific users. destroy. snapshot. the remaining characters in the set name have the same restrictions as normal ZFS file system names. or everyone. and so on. groups. After the @ symbol.
241
.
■
ZFS delegated administration provides features similar to the RBAC security model. Groups of permissions called permission sets can be defined. Permission sets begin with the @ symbol and are limited to 64 characters in length. mount. A permission set can later be updated.C H A P T E R
Oracle Solaris ZFS Delegated Administration
9
9
This chapter describes how to use delegated administration to allow nonprivileged users to perform ZFS administration tasks. ZFS delegation provides the following advantages for administering ZFS storage pools and file systems:
■ ■
Permissions follow the ZFS storage pool whenever a pool is migrated. Provides dynamic inheritance where you can control how the permissions propagate through the file systems. and all of the consumers of the set automatically get the change.

Permissions can be delegated either locally to the current dataset only or to all descendents of the current dataset. and Privileges.
Must also have the permission that is being allowed.
Delegating ZFS Permissions
You can use the zfs allow command to delegate permissions on ZFS datasets to non-root users in the following ways:
■ ■
Individual permissions can be delegated to a user. For information about using RBAC to manage general Oracle Solaris administration tasks. the delegation property is enabled.
■
The following table describes the operations that can be delegated and any dependent permissions that are required to perform the delegated operations.
Disabling ZFS Delegated Permissions
You control the delegated administration features by using a pool's delegation property. see Part III.
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.
Permission (Subcommand) Description Dependencies
allow
The permission to grant permissions that you have to another user. Rights Profiles. You can delegate permissions to specific file systems. or everyone. Newly created file systems can automatically pick up permissions. For example:
# zpool get delegation users NAME PROPERTY VALUE SOURCE users delegation on default # zpool set delegation=off users # zpool get delegation users NAME PROPERTY VALUE SOURCE users delegation off local
By default. “Roles.
■
Consider using delegated administration for distributing ZFS tasks. group. group.” in System Administration Guide: Security Services.zfs/snapshot directory. For example. Groups of individual permissions can be delegated as a permission set to a user. a user with explicit permissions can create a snapshot over NFS in the appropriate . or everyone.Delegating ZFS Permissions
■ ■
Can be configured so that only the creator of a file system can destroy the file system. Provides simple NFS administration.

Must also have the mount permission. and create and destroy volume device links.
Must also have the create permission and the mount permission in the original file system. you can delegate administration of the following ZFS properties to non-root users:
■ ■ ■
aclinherit atime canmount
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. Must also have the mount permission. Must also have the mount permission and the create permission. The permission to promote a clone to a dataset.
create
destroy hold mount
promote
Must also have the mount permission and the promote permission in the original file system. The permission to rename a dataset. The permission to share and unshare a dataset. The permission to hold a snapshot. or change permission:
■ ■ ■ ■ ■
groupquota groupused userprop userquota userused
In addition. The permission to create descendent file systems with the zfs receive command. The permission to roll back a snapshot. The permission to destroy a dataset. The permission to send a snapshot stream.
receive
rename
rollback send
share
snapshot
You can delegate the following set of permissions but a permission might be limited to access. read. The permission to create descendent datasets. Must also have the create permission and the mount permission in the new parent. The permission to mount and unmount a dataset. The permission to create a snapshot of a dataset.Delegating ZFS Permissions
Permission (Subcommand)
Description
Dependencies
clone
The permission to clone any of the dataset's snapshots.

.. as a group name. Permission sets can be used by other zfs allow commands for the specified file system and its descendents.Delegating ZFS Permissions
Multiple entities can be specified as a comma-separated list. Permission sets are evaluated dynamically. If no -uge options are specified. For more information.. The following zfs allow syntax (in bold) identifies how permissions and permission sets are specified:
zfs allow [-s] . Permissions can be aggregated into permission sets and are identified by the -s option. If neither option is specified. then the permissions are allowed for the file system or volume and all of its descendents.mount.. mount. The -d option indicates that the permissions are allowed for the descendent datasets and not for this dataset.snapshot -------------------------------------------------------------
To remove these permissions. destroy. but the name must begin with an at sign (@) and can be no more than 64 characters in length.” use the -u or -g option. unless the -l option is also specified.. filesystem | volume
The -l option indicates that the permissions are allowed for the specified dataset and not its descendents.. then the argument is interpreted preferentially as the keyword everyone. To specify a user or group named “everyone. . The following zfs allow syntax (in bold) identifies how the permissions are delegated:
zfs allow [-ld] . assume that you delegated create. Permission names are the same as ZFS subcommands and properties.. Permission sets follow the same naming requirements as ZFS file systems. then as a user name. The -c option delegates create-time permissions.destroy.] filesystem | volume
Multiple permissions can be specified as a comma-separated list.. use the -g option. To specify a group with the same name as a user.
Removing ZFS Delegated Permissions (zfs unallow)
You can remove previously delegated permissions with the zfs unallow command.snapshot tank/cindys # zfs allow tank/cindys ------------------------------------------------------------Local+Descendent permissions on (tank/cindys) user cindys create.destroy. so changes to a set are immediately updated. and snapshot permissions as follows:
# zfs allow cindys create. unless the -d option is also specified. you would use the following syntax:
# zfs unallow cindys tank/cindys # zfs allow tank/cindys
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. perm|@setname [.. For example. and lastly. see the preceding section.mount.

see Table 6–1. In the following example. a reservation is automatically set to the initial size of the volume so that unexpected behavior doesn't occur. using ZFS on a Solaris system with zones installed. You must be careful when changing the size of the volume. and ZFS rights profiles. If you are using a Solaris system with zones installed. ZFS alternate root pools. you might introduce inconsistencies if you attempt to roll back the snapshot or create a clone from the snapshot. For information about using ZFS volumes in a global zone.rdsk}/pool directory. ZFS volumes are identified as devices in the /dev/zvol/{dsk. see “Adding ZFS Volumes to a Non-Global Zone” on page 258. you cannot create or clone a ZFS volume in a non-global zone. tank/vol. For information about file system properties that can be applied to volumes. For example.
253
. a 5-GB ZFS volume. In addition. data corruption might occur. is created:
# zfs create -V 5gb tank/vol
When you create a volume. Any attempt to do so will fail.10
C H A P T E R
■ ■ ■ ■
1 0
Oracle Solaris ZFS Advanced Topics
This chapter describes ZFS volumes. if the size of the volume shrinks. if you create a snapshot of a volume that changes in size. The following sections are provided in this chapter: “ZFS Volumes” on page 253 “Using ZFS on a Solaris System With Zones Installed” on page 256 “Using ZFS Alternate Root Pools” on page 261 “ZFS Rights Profiles” on page 262
ZFS Volumes
A ZFS volume is a dataset that represents a block device.

1 16 2097136 2097136 /dev/zvol/dsk/rpool/swap2 256. For example:
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. The dump device requires no administration after it is set up. a dump device is created on a ZFS volume in the ZFS root pool. use the swap and dumpadm commands as in previous Solaris releases. install the COMSTAR package. You can create and configure a ZFS volume to be shared as an iSCSI logical unit (LUN). For information about adjusting the size of the swap and dump volumes. For example:
# zfs create -V 2G rpool/swap2 # swap -a /dev/zvol/dsk/rpool/swap2 # swap -l swapfile dev swaplo blocks free /dev/zvol/dsk/rpool/swap 256.
# pkg install solaris/storage-server
Create a ZFS volume to be used as an iSCSI target and then create the SCSI-block-device-based LUN. For example:
# dumpadm Dump content: Dump device: Savecore directory: Savecore enabled: kernel pages /dev/zvol/dsk/rpool/dump (dedicated) /var/crash/t2000 yes
If you need to change your swap area or dump device after the system is installed or upgraded.ZFS Volumes
Using a ZFS Volume as a Swap or Dump Device
During installation of a ZFS root file system or a migration from a UFS root file system. a swap device is created on a ZFS volume in the ZFS root pool. If you need to create an additional swap volume.5 16 4194288 4194288
Do not swap to a file on a ZFS file system. A ZFS swap file configuration is not supported. see “Adjusting the Sizes of Your ZFS Swap and Dump Devices” on page 132.
Using a ZFS Volume as a Solaris iSCSI LUN
The Common Multiprotocol SCSI Target (COMSTAR) software framework enables you to convert any Solaris host into a SCSI target device that can be accessed over a storage network by initiator hosts.3 swaplo blocks free 16 8257520 8257520
During installation of a ZFS root file system or a migration from a UFS root file system. For example:
# swap -l swapfile dev /dev/zvol/dsk/rpool/swap 253. First. create a ZFS volume of a specific size and then enable swap on that device.

Like an NFS shared file system. In the following example. the LUN view is shared to all clients. Identify the LUN GUID and then share the LUN view.---------------600144f000144f1dafaa4c0faff20001 2147483648 /dev/zvol/rdsk/tank/volumes/v2 # sbdadm list-lu Found 1 LU(s) GUID DATA SIZE SOURCE -------------------------------.com/observatory/entry/iscsi_san_part_2_the
A ZFS volume as an iSCSI target is managed just like any other ZFS dataset except that you cannot rename the dataset. go to the following sites:
■ ■ ■
http://wikis.
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. For information about creating the iSCSI targets. or export the pool while the ZFS volumes are shared as iSCSI LUNs.com/display/OpenSolarisInfo/COMSTAR+Administration http://blogs. an iSCSI target that is imported on a different system is shared appropriately.---------------600144f000144f1dafaa4c0faff20001 2147483648 /dev/zvol/rdsk/tank/volumes/v2
You can expose the LUN views to all clients or selected clients. You will see messages similar to the following:
# zfs rename tank/volumes/v2 tank/volumes/v1 cannot rename ’tank/volumes/v2’: dataset is busy # zpool export tank cannot export ’tank’: pool is busy
All iSCSI target configuration information is stored within the dataset.sun.ZFS Volumes
# zfs create -V 2g tank/volumes/v2 # sbdadm create-lu /dev/zvol/rdsk/tank/volumes/v2 Created the following LU: GUID DATA SIZE SOURCE -------------------------------.sun.sun.------------------.
# stmfadm list-lu LU Name: 600144F000144F1DAFAA4C0FAFF20001 # stmfadm add-view 600144F000144F1DAFAA4C0FAFF20001 # stmfadm list-view -l 600144F000144F1DAFAA4C0FAFF20001 View Entry: 0 Host group : All Target group : All LUN : 0
The next step is to create the iSCSI targets.com/observatory/entry/iscsi_san http://blogs.------------------. rollback a volume snapshot.

and Resource Management.” in System Administration Guide: Oracle Solaris Zones. This operation is identical to adding any other type of file system to a zone and should be used when the primary purpose is solely to share common disk space. The zoneadm clone command will create a ZFS snapshot of the source zonepath and set up the target zonepath.Using ZFS on a Solaris System With Zones Installed
Using ZFS on a Solaris System With Zones Installed
The following sections describe how to use ZFS on a system with Oracle Solaris zones:
■ ■ ■ ■ ■ ■
“Adding ZFS File Systems to a Non-Global Zone” on page 257 “Delegating Datasets to a Non-Global Zone” on page 257 “Adding ZFS Volumes to a Non-Global Zone” on page 258 “Using ZFS Storage Pools Within a Zone” on page 258 “Managing ZFS Properties Within a Zone” on page 259 “Understanding the zoned Property” on page 260
Keep the following points in mind when associating ZFS datasets with zones:
■
You can add a ZFS file system or a clone to a non-global zone with or without delegating administrative control. You cannot use the zfs clone command to clone a zone. Due to CR 6449301. Instead. Adding a dataset allows the non-global zone to share disk space with the global zone. though the zone administrator cannot control properties or create new file systems in the underlying file system hierarchy. Consider the following when working with ZFS on a system with Oracle Solaris zones installed:
■
A ZFS file system that is added to a non-global zone must have its mountpoint property set to legacy. You cannot associate ZFS snapshots with zones at this time.
■
■
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. You can add a ZFS volume as a device to non-global zones. The zone administrator cannot affect datasets that have not been added to the zone. For more information. a ZFS dataset refers to a file system or a clone. When both a source zonepath and a target zonepath reside on a ZFS file system and are in the same pool. ZFS also allows datasets to be delegated to a non-global zone. zoneadm clone will now automatically use the ZFS clone to clone a zone. see Part II. do not add a ZFS dataset to a non-global zone when the non-global zone is configured. Oracle Solaris 10 Containers. add a ZFS dataset after the zone is installed. including exceeding any top-level quotas set on the delegated dataset. The zone administrator can create and destroy file systems or clones within that dataset.
■ ■
In the following sections. giving complete control over the dataset and all its children to the zone administrator. “Oracle Solaris Zones. as well as modify properties of the datasets.

and Resource Management. set the mountpoint property in the global zone as follows:
# zfs set mountpoint=legacy tank/zone/zion
You can add a ZFS file system to a non-global zone by using the zonecfg command's add fs subcommand. and so on. In the following example. readonly. to the already configured zion zone. The file system cannot be remounted in a different location. and the file system cannot already be mounted in another location.” in System Administration Guide: Oracle Solaris Zones. “Oracle Solaris Zones. see Part II. The global zone administrator is responsible for setting and controlling properties of the file system. For more information about the zonecfg command and about configuring resource types with zonecfg. a ZFS file system is added to a non-global zone by a global zone administrator from the global zone:
# zonecfg -z zion zonecfg:zion> add fs zonecfg:zion:fs> set type=zfs zonecfg:zion:fs> set special=tank/zone/zion zonecfg:zion:fs> set dir=/export/shared zonecfg:zion:fs> end
This syntax adds the ZFS file system. ZFS supports adding datasets to a non-global zone through the use of the zonecfg command's add dataset subcommand.
Delegating Datasets to a Non-Global Zone
To meet the primary goal of delegating the administration of storage to a zone. if the tank/zone/zion file system will be added to a non-global zone. a ZFS file system is delegated to a non-global zone by a global zone administrator from the global zone. The zone administrator can create and destroy files within the file system. A ZFS file system that is added to a non-global zone must have its mountpoint property set to legacy. nor can the zone administrator change properties on the file system such as atime.Using ZFS on a Solaris System With Zones Installed
Adding ZFS File Systems to a Non-Global Zone
You can add a ZFS file system as a generic file system when the goal is solely to share space with the global zone. which is mounted at /export/shared. tank/zone/zion. In the following example.
# zonecfg -z zion zonecfg:zion> add dataset zonecfg:zion:dataset> set name=tank/zone/zion zonecfg:zion:dataset> end
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. Oracle Solaris 10 Containers. The mountpoint property of the file system must be set to legacy. compression. For example.

■
In a global zone. Even if physical devices are added to a zone by using the zonecfg command's add device subcommand. The zone administrator can set file system properties. is not allowed from within a zone. this syntax causes the ZFS file system tank/zone/zion to be visible within the already configured zion zone.
258 Oracle Solaris ZFS Administration Guide • January 2011
. the zone administrator can create snapshots and clones. and otherwise control the entire file system hierarchy. The delegated administration model centralizes control of physical storage devices within the global zone and control of virtual storage to non-global zones. any command that modifies the physical characteristics of the pool. For example:
# zonecfg -z zion zonecfg:zion> add dataset zonecfg:zion:dataset> set name=tank/volumes/vol1 zonecfg:zion:dataset> end
The above syntax means that the zone administrator can manage the volume's properties and data in the non-global zone. the zpool command does not allow the creation of any new pools within the zone.Using ZFS on a Solaris System With Zones Installed
Unlike adding a file system. a privileged zone administrator can create a ZFS volume as descendent of a previously delegated file system. or removing devices. as well as create descendent file systems. For example:
# zonecfg -z zion zonecfg:zion> add device zonecfg:zion:device> set match=/dev/zvol/dsk/tank/volumes/vol2 zonecfg:zion:device> end
The above syntax means that only the volume data can be accessed in the non-global zone.
Adding ZFS Volumes to a Non-Global Zone
You can add or create a ZFS volume in a non-global zone or you can add access to a volume's data in a non-global zone in the following ways:
■
In a non-global zone. use the zonecfg add device subcommand and specify a ZFS volume whose data can be accessed in a non-global zone. In addition. use the zonecfg add dataset subcommand and specify a ZFS volume to be added to a non-global zone. such as creating. For example:
# zfs create -V 2g tank/zone/zion/vol1
The above syntax means that the zone administrator can manage the volume's properties and data in the non-global zone.
Using ZFS Storage Pools Within a Zone
ZFS storage pools cannot be created or modified within a zone. or if files are used. Although a pool-level dataset can be added to a zone.
■
In a global zone. adding.

zoned. The zone administrator cannot change the sharenfs property because non-global zones cannot act as NFS servers. consider the following configuration:
global# zfs list -Ho name tank tank/home tank/data tank/data/matrix tank/data/zion tank/data/zion/home
If tank/data/zion were added to a zone. In addition. and datasets that are not part of the parent hierarchy are not visible at all. while the dataset itself is writable. reservation sharenfs. the zone administrator can control specific dataset properties. except for quota and reservation properties. zoned
tank/data/zion/home
Note that every parent of tank/zone/zion is visible as read-only.Using ZFS on a Solaris System With Zones Installed
Managing ZFS Properties Within a Zone
After a dataset is delegated to a zone. The zone administrator cannot change the zoned property because doing so would expose a security risk as described in the next section. Privileged users in the zone can change any other settable property. This behavior allows the global zone administrator to control the disk space consumption of all datasets used by the non-global zone.
Dataset Visible Writable Immutable Properties
tank tank/home tank/data tank/data/matrix tank/data/zion
Yes No Yes No Yes Yes
No No Yes Yes
sharenfs. quota.
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. all descendents are writable. For example. each dataset would have the following properties. all its ancestors are visible as read-only datasets. After a dataset is delegated to a zone. as are all of its descendents. the sharenfs and mountpoint properties cannot be changed by the global zone administrator after a dataset has been delegated to a non-global zone.

ensure that the mountpoint property for the dataset and all its descendents are set to reasonable values and that no setuid binaries exist. the zoned property must be manually cleared by the global zone administrator if you want to reuse the dataset in any way. This behavior is due to the inherent security risks associated with these tasks. the zoned property can be turned off by using the zfs set or zfs inherit command. or setuid binaries might exist on the file systems. To address the latter. tank/zone/zion has been delegated to a zone. After a dataset has been delegated to a non-global zone and is under the control of a zone administrator.mountpoint -r tank/zone NAME ZONED MOUNTPOINT tank/zone/global off /tank/zone/global tank/zone/zion on /tank/zone/zion # zfs mount tank/zone/global /tank/zone/global tank/zone/zion /export/zone/zion/root/tank/zone/zion
Note the difference between the mountpoint property and the directory where the tank/zone/zion dataset is currently mounted. The mountpoint property reflects the property as it is stored on disk. If the zoned property is set. When a dataset is removed from a zone or a zone is destroyed. the zone administrator could affect the global zone's namespace. After you have verified that no security vulnerabilities are left. The zoned property is a boolean value that is automatically turned on when a zone containing a ZFS dataset is first booted. In addition. symbolic links. or otherwise questionable contents that might adversely affect the security of the global zone.zoned. A zone administrator does not need to manually turn on this property. Otherwise. or turn off the setuid property.Using ZFS on a Solaris System With Zones Installed
Understanding the zoned Property
When a dataset is delegated to a non-global zone. To prevent accidental security risks. the system might behave in unpredictable ways. its contents can no longer be trusted. there might be setuid binaries. Because an untrusted user has had complete access to the dataset and its descendents. the mountpoint property might be set to bad values. not where the dataset is currently mounted on the system. the dataset cannot be mounted or shared in the global zone. Only change the property if you are sure the dataset is no longer in use by a non-global zone. the dataset must be specially marked so that certain properties are not interpreted within the context of the global zone. the zoned property is not automatically cleared. Before setting the zoned property to off. In the following example. As with any file system.
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. the mountpoint property cannot be interpreted in the context of the global zone. while tank/zone/global has not:
# zfs list -o name. ZFS uses the zoned property to indicate that a dataset has been delegated to a non-global zone at one point in time. If the zoned property is turned off while a dataset is in use within a zone.

the mount point of the root file system is automatically set to /. which is the equivalent of the alternate root value. a pool called morpheus is imported with /mnt as the alternate root path.Using ZFS Alternate Root Pools
Using ZFS Alternate Root Pools
When a pool is created. This feature also can be used when you are mounting removable media as described in the preceding section.5G 8K /mnt
Note the single file system. This file system can then be exported and imported under an arbitrary alternate root pool on a different system by using -R alternate root value syntax. The host system maintains information about the pool so that it can detect when the pool is unavailable. a pool called morpheus is created with /mnt as the alternate root path:
# zpool create -R /mnt morpheus c0t0d0 # zfs list morpheus NAME USED AVAIL REFER MOUNTPOINT morpheus 32. and they want it to be mounted wherever they choose on the target system. but under some temporary directory where repairs can be performed.5K 33.5K 33.
# zpool export morpheus # zpool import morpheus cannot mount ’/’: directory is not empty # zpool export morpheus # zpool import -R /mnt morpheus # zfs list morpheus NAME USED AVAIL REFER MOUNTPOINT morpheus 32. In the following example. /mnt. users typically want a single file system. Although useful for normal operations.
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. where the mount points should not be interpreted in context of the current root. An alternate root pool does not persist across system reboots. The mount point that is stored on disk is / and the full path to /mnt is interpreted only in this initial context of the pool creation. To solve this problem. it is intrinsically tied to the host system. whose mount point is the alternate root of the pool. and all mount points are modified to be relative to the root of the pool. In these circumstances. In the following example. When an alternate root pool is created by using the zpool create -R option. this information can prove a hindrance when you are booting from alternate media or creating a pool on removable media.
Creating ZFS Alternate Root Pools
The most common reason for creating an alternate root pool is for use with removable media. This feature allows for recovery situations. This example assumes that morpheus was previously exported. ZFS provides an alternate root pool feature.5G 8K /mnt
Importing Alternate Root Pools
Pools can also be imported using an alternate root. morpheus.

ZFS can encounter three basic types of errors:
■ ■ ■
“Missing Devices in a ZFS Storage Pool” on page 264 “Damaged Devices in a ZFS Storage Pool” on page 264 “Corrupted ZFS Data” on page 264
Note that a single pool can experience all three errors. and so on.11
C H A P T E R
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1 1
Oracle Solaris ZFS Troubleshooting and Pool Recovery
This chapter describes how to identify and recover from ZFS failures. so a complete repair procedure involves finding and correcting one error. Information for preventing failures is provided as well. ZFS can exhibit many different failures. The following sections are provided in this chapter: “Identifying ZFS Failures” on page 263 “Checking ZFS File System Integrity” on page 265 “Resolving Problems With ZFS” on page 267 “Repairing a Damaged ZFS Configuration” on page 272 “Resolving a Missing Device” on page 272 “Replacing or Repairing a Damaged Device” on page 274 “Repairing Damaged Data” on page 283 “Repairing an Unbootable System” on page 287
Identifying ZFS Failures
As a combined file system and volume manager. This chapter begins by outlining the various failures. This chapter concludes by discussing how to repair the problems. then discusses how to identify them on a running system.
263
. proceeding to the next error.

Data errors are recorded as they are encountered. this scenario requires restoring data from backups. such as a random I/O error while the controller is having problems. Examples include the following:
■ ■ ■ ■
Transient I/O errors due to a bad disk or controller On-disk data corruption due to cosmic rays Driver bugs resulting in data being transferred to or from the wrong location A user overwriting portions of the physical device by accident
In some cases. Most often. the damage is permanent. these errors are transient. and they can be controlled through routine pool scrubbing as explained in the following section. the next scrubbing pass recognizes that the corruption is no longer present and removes any trace of the error from the system. the pool continues to be accessible. if an administrator accidentally overwrites part of a disk.
Corrupted ZFS Data
Data corruption occurs when one or more device errors (indicating one or more missing or damaged devices) affects a top-level virtual device.Identifying ZFS Failures
Missing Devices in a ZFS Storage Pool
If a device is completely removed from the system. the original data is lost forever. and the device does not need to be replaced. When a corrupted block is removed. no type of hardware failure has occurred. one half of a mirror can experience thousands of device errors without ever causing data corruption. If an error is encountered on the other side of the mirror in the exact same location. A pool might become FAULTED. If one disk in a mirrored or RAID-Z device is removed. Data corruption is always permanent and requires special consideration during repair. Even still. whether the damage is permanent does not necessarily indicate that the error is likely to occur again. ZFS detects that the device cannot be opened and places it in the REMOVED state. Depending on the data replication level of the pool. For example. corrupted data is the result. Identifying the exact problem with a device is not an easy task and is covered in more detail in a later section. such as on-disk corruption. under the following conditions:
■ ■ ■
If all components of a mirror are removed If more than one device in a RAID-Z (raidz1) device is removed If top-level device is removed in a single-disk configuration
Damaged Devices in a ZFS Storage Pool
The term “damaged” covers a wide variety of possible errors. this removal might or might not result in the entire pool becoming unavailable. Even if the underlying devices are repaired or replaced. For example. which means no data is accessible until the device is reattached. In other cases.
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.

ZFS provides a mechanism to perform routine checking of all inconsistencies. but can introduce additional problems when the log cannot be rolled back. Traditionally. If your pool is not redundant. Because a traditional file system is not transactional. This utility has traditionally served two purposes. Many problems can be avoided by using redundant pools. the way in which data is written is inherently vulnerable to unexpected failure causing file system inconsistencies. known as scrubbing. unreferenced blocks. The only way for inconsistent data to exist on disk in a ZFS configuration is through hardware failure (in which case the pool should have been redundant) or when a bug exists in the ZFS software.
File System Repair
With traditional file systems. see “Repairing ZFS Storage Pool-Wide Damage” on page 286. this task requires unmounting the file system and running the fsck utility. The fsck utility repairs known problems specific to UFS file systems. the error is logged internally so that you can obtain quick overview of all known errors within the pool. those of file system repair and file system validation. This scenario results in downtime that is proportional to the size of the file system being checked.
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. If your pool is damaged due to failing hardware or a power outage. the fsck utility validates that the data on disk has no problems.Checking ZFS File System Integrity
Checking ZFS File System Integrity
No fsck utility equivalent exists for ZFS. Most ZFS storage pool problems are generally related to failing hardware or power failures.
File System Validation
In addition to performing file system repair. the risk that file system corruption can render some or all of your data inaccessible is always present. either through scrubbing or when accessing a file on demand. possibly taking the system to single-user mode in the process. is commonly used in memory and other systems as a method of detecting and preventing errors before they result in a hardware or software failure. Instead of requiring an explicit utility to perform the necessary checking. or other inconsistent file system structures are possible. This feature.
Controlling ZFS Data Scrubbing
Whenever ZFS encounters an error. bad link counts. The addition of journaling does solve some of these problems.

This operation might negatively impact performance. For example:
# zpool scrub -s tank
In most cases. or if power consumption is not a concern. You can stop a scrubbing operation that is in progress by using the -s option. 90. Scrubbing proceeds as fast as the devices allow. though the priority of any I/O remains below that of normal operations. a scrubing operation to ensure data integrity should continue to completion.44% done config: NAME tank mirror-0 c1t0d0 c1t1d0 STATE ONLINE ONLINE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0 0 0 0 0 0 0
errors: No known data errors
Only one active scrubbing operation per pool can occur at one time. though the pool's data should remain usable and nearly as responsive while the scrubbing occurs. For more information about interpreting zpool status output. Routine scrubbing has the side effect of preventing power management from placing idle disks in low-power mode.
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. then this issue can safely be ignored. see “Querying ZFS Storage Pool Status” on page 105. Performing routine scrubbing guarantees continuous I/O to all disks on the system. For example:
# zpool status -v tank pool: tank state: ONLINE scan: scrub in progress since Mon Jun 7 12:07:52 2010 201M scanned out of 222M at 9. If the system is generally performing I/O all the time. Stop a scrubbing operation at your own discretion if system performance is impacted by the operation. use the zpool scrub command. 0h0m to go 0 repaired. To initiate an explicit scrub.Checking ZFS File System Integrity
Explicit ZFS Data Scrubbing
The simplest way to check data integrity is to initiate an explicit scrubbing of all data within the pool. This operation traverses all the data in the pool once and verifies that all blocks can be read.55M/s. For example:
# zpool scrub tank
The status of the current scrubbing operation can be displayed by using the zpool status command.

Previous ZFS commands that modified pool state information can be displayed by using the zpool history command.Resolving Problems With ZFS
ZFS Data Scrubbing and Resilvering
When a device is replaced. though multiple problems can exist. the fmd message directs you to the zpool status command for further recovery instructions. I/O. only one such action can occur at a given time in the pool.
■ ■
Most ZFS troubleshooting involves the zpool status command. data corruption errors generally imply that one of the devices has failed. In most cases. a resilvering operation is initiated to move data from the good copies to the new device. ZFS failures as reported by fmd are displayed on the console as well as the system messages file. For more information about resilvering. For example:
# zpool history tank History for ’tank’: 2010-07-15. Note that the command only identifies a single problem with a pool. In addition.12:06:50 zpool create tank mirror c0t1d0 c0t2d0 c0t3d0
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. use the zpool history command to identify the ZFS commands that preceded the error scenario. device. a ZFS diagnostic engine diagnoses and reports pool failures and device failures. The basic recovery process is as follows:
■
If appropriate. This action is a form of disk scrubbing. a resilvering operation suspends the current scrubbing and restarts it after the resilvering is completed. see “Viewing Resilvering Status” on page 281. Checksum. presenting you with a suggested action and a link to a knowledge article for more information. For example. If a scrubbing operation is in progress. and pool errors associated with these failures are also reported. but replacing the failed device might not resolve all of the data corruption problems. Therefore. Pool and device failures are reported through ZFS/FMA diagnostic messages. This command analyzes the various failures in a system and identifies the most severe problem.
Resolving Problems With ZFS
The following sections describe how to identify and resolve problems with your ZFS file systems or storage pools:
■ ■ ■
“Determining If Problems Exist in a ZFS Storage Pool” on page 268 “Reviewing zpool status Output” on page 268 “System Reporting of ZFS Error Messages” on page 272
You can use the following features to identify problems with your ZFS configuration:
■
Detailed ZFS storage pool information can be displayed by using the zpool status command.

■
Identify the errors through the fmd messages that are displayed on the system console or in the /var/adm/messages file. if applicable. Repair the failures. Verifying the recovery by using the zpool status -x command.
This section describes how to interpret zpool status output in order to diagnose the type of failures that can occur. note that checksums are disabled for the tank/erick file system. Although most of the work is performed automatically by the command. Backing up your restored configuration. the command displays the complete status for all pools (or the requested pool. then the command displays the following:
# zpool status -x all pools are healthy
Without the -x flag. Subsequent sections describe how to repair the various problems that you might encounter. it is important to understand exactly what problems are being identified in order to diagnose the failure. if specified on the command line).
Determining If Problems Exist in a ZFS Storage Pool
The easiest way to determine if any known problems exist on a system is to use the zpool status -x command. Find further repair instructions by using the zpool status -x command.12:07:01 zfs set checksum=off tank/erick
In this output. which involves the following steps:
■ ■ ■ ■
■ ■
Replacing the faulted or missing device and bring it online.Resolving Problems With ZFS
2010-07-15. If no unhealthy pools exist on the system. even if the pools are otherwise healthy. see “Querying ZFS Storage Pool Status” on page 105. Sufficient replicas exist for
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. This command describes only pools that are exhibiting problems.
Reviewing zpool status Output
The complete zpool status output looks similar to the following:
# zpool status tank # zpool status tank pool: tank state: DEGRADED status: One or more devices could not be opened. This configuration is not recommended. Restoring the faulted configuration or corrupted data from a backup.12:06:58 zfs create tank/erick 2010-07-15. For more information about command-line options to the zpool status command.

or if no scrub was requested. Identifies the current status of a scrub operation.Resolving Problems With ZFS
the pool to continue functioning in a degraded state.com/msg/ZFS-8000-2Q scrub: none requested config: NAME tank mirror-0 c1t0d0 c1t1d0 STATE READ WRITE CKSUM DEGRADED 0 0 0 DEGRADED 0 0 0 ONLINE 0 0 0 UNAVAIL 0 0 0 cannot open
errors: No known data errors
This output is described next:
Overall Pool Status Information
This section in the zpool status output contains the following fields. Refers to a knowledge article containing detailed repair information.sun. A recommended action for repairing the errors. action: Attach the missing device and online it using ’zpool online’. Describes what is wrong with the pool. This information refers only to the ability of the pool to provide the necessary replication level. FAULTED. UNAVAIL. This field is omitted if no errors are found. This field is omitted if no errors are found. or OFFLINE. Online articles are updated more often than this guide can be updated. some of which are only displayed for pools exhibiting problems: pool state status action see Identifies the name of the pool. If the state is anything but ONLINE. The state can be one of the following: ONLINE. always reference them for the most up-to-date repair procedures. DEGRADED. the fault tolerance of the pool has been compromised. Identifies known data errors or the absence of known data errors. This field is omitted if no errors are found. a scrub is in progress. as well as their state and any errors generated from the devices. Indicates the current health of the pool. which might include the date and time that the last scrub was completed. So.
scrub
errors
Pool Configuration Information
The config field in the zpool status output describes the configuration of the devices in the pool. see: http://www. These errors are divided into three categories:
Chapter 11 • Oracle Solaris ZFS Troubleshooting and Pool Recovery 269
. The second section of the configuration output displays error statistics.

If a device is FAULTED. The following zpool status scrub status messages are provided:
■
Scrub in-progress report. Finally. If the last scrub ended recently.69% done
■
Scrub completion message. any known data corruption has been discovered. If the device is undergoing resilvering. For example:
scrub repaired 0 in 0h12m with 0 errors on Mon Jun 7 09:08:48 2010
■
Ongoing scrub cancellation message. though this information can be used to determine the accuracy of the data corruption error reporting. For information about monitoring resilvering progress. aiding in the diagnosis of failures. meaning that the device returned corrupted data as the result of a read request
These errors can be used to determine if the damage is permanent. this field indicates whether the device is inaccessible or whether the data on the device is corrupted. see “Determining the Type of Device Failure” on page 274.Resolving Problems With ZFS
■ ■ ■
READ – I/O errors that occurred while issuing a read request WRITE – I/O errors that occurred while issuing a write request CKSUM – Checksum errors.33M/s. most likely.90G scanned out of 16. ZFS successfully retrieved the good data and attempted to heal the damaged data from existing replicas. 11. If the device is in a redundant configuration. For more information about interpreting these errors. while no errors appear at the mirror or RAID-Z device level. This information is distinct from whether any errors are detected on the system. For example:
scan: scrub canceled on Thu Jun 3 09:39:39 2010
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. A small number of I/O errors might indicate a temporary outage.2G at 9.
Scrubbing Status
The scrub section of the zpool status output describes the current status of any explicit scrubbing operations. These errors do not necessarily correspond to data corruption as interpreted by applications. 0h26m to go 0 repaired. This information expands on the state field. see “Viewing Resilvering Status” on page 281. In such cases. the devices might show uncorrectable errors. while a large number might indicate a permanent problem with the device. this field displays the current progress. For example:
scan: scrub in progress since Mon Jun 7 08:56:04 2010 1. additional auxiliary information is displayed in the last column of the zpool status output.

only the number of errors found is displayed. A complete list of errors and their specifics can be found by using the zpool status -v option.
Data Corruption Errors
The zpool status command also shows whether any known errors are associated with the pool. ZFS maintains a persistent log of all data errors associated with a pool. Make sure the affected devices are connected. see “Checking ZFS File System Integrity” on page 265. see “Identifying the Type of Data Corruption” on page 284. Their presence indicates that at least one application experienced an I/O error due to corrupt data within the pool. By default. http://www. This log is rotated whenever a complete scrub of the system finishes. These messages can also be tracked by using the fmdump command. For more information about interpreting data corruption errors. For more information about the data scrubbing and how to interpret this information. These errors might have been found during data scrubbing or during normal operation. then run ’zpool clear’.sun. For example:
# zpool pool: state: status: action: see: scrub: config: status -v tank UNAVAIL One or more devices are faulted in response to IO failures.Resolving Problems With ZFS
Scrub completion messages persist across system reboots. Device errors within a redundant pool do not result in data corruption and are not recorded as part of this log. Data corruption errors are always fatal.com/msg/ZFS-8000-HC scrub completed after 0h0m with 0 errors on Tue Feb 2 13:08:42 2010 NAME tank c1t0d0 c1t1d0 STATE UNAVAIL ONLINE UNAVAIL READ WRITE CKSUM 0 0 0 insufficient replicas 0 0 0 4 1 0 cannot open
errors: Permanent errors have been detected in the following files: /tank/data/aaa /tank/data/bbb /tank/data/ccc
A similar message is also displayed by fmd on the system console and the /var/adm/messages file.
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.

If this cache file is corrupted or somehow becomes out of sync with configuration information that is stored on disk. This state means that ZFS was unable to open the device when the pool was first accessed. the pool can no longer be opened. no notification occurs.
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If ZFS detects a device error and automatically recovers from it. Subsequent accesses do not generate a message. or the device has since become unavailable. This situation can also manifest as a partial configuration that is missing an unknown number of top-level virtual devices. Such errors do not constitute a failure in the pool redundancy or in data integrity. ZFS also displays syslog messages when events of interest occur. A similar message is sent if the device is later brought online.
Repairing a Damaged ZFS Configuration
ZFS maintains a cache of active pools and their configuration in the root file system. This message is only logged the first time it is detected. the fault manager daemon reports these errors through syslog messages as well as the fmdump command.
Resolving a Missing Device
If a device cannot be opened. Data corruption – If any data corruption is detected. see “Migrating ZFS Storage Pools” on page 115. In either case. The following scenarios generate events to notify the administrator:
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Device state transition – If a device becomes FAULTED. This situation typically results in a pool disappearing from the system when it should otherwise be available. If the device causes a top-level virtual device to be
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. though arbitrary corruption is always possible given the qualities of the underlying storage.Repairing a Damaged ZFS Configuration
System Reporting of ZFS Error Messages
In addition to persistently tracking errors within the pool. restoring the pool to health. the configuration can be recovered by exporting the pool (if it is visible at all) and re-importing it. ZFS logs a message describing when and where the corruption was detected. Pool failures and device failures – If a pool failure or a device failure occurs. such errors are typically the result of a driver problem accompanied by its own set of error messages. For information about importing and exporting pools. it displays the UNAVAIL state in the zpool status output. Moreover. ZFS tries to avoid this situation. ZFS logs a message indicating that the fault tolerance of the pool might be compromised.

TYPE: Fault. confirm that the pool with the replaced device is healthy. An attempt will be made to activate a hot spare if available. REV: 1.
To view more detailed information about the device problem and the resolution. If you determine that the device is faulty.Resolving a Missing Device
unavailable. Otherwise. you might see a message similar to the following from fmd after a device failure:
SUNW-MSG-ID: ZFS-8000-FD. use the zpool status -x command. For example. SEVERITY: Major EVENT-TIME: Thu Jun 24 10:42:36 PDT 2010 PLATFORM: SUNW. Sufficient replicas exist for the pool to continue functioning in a degraded state. then nothing in the pool can be accessed. see: http://www.com/msg/ZFS-8000-2Q scrub: scrub completed after 0h0m with 0 errors on Tue Feb 2 13:15:20 2010 config: NAME tank mirror-0 c1t0d0 c1t1d0 STATE READ WRITE CKSUM DEGRADED 0 0 0 DEGRADED 0 0 0 ONLINE 0 0 0 UNAVAIL 0 0 0 cannot open
errors: No known data errors
You can see from this output that the missing c1t1d0 device is not functioning. use the zpool online command to bring online the replaced device. Refer to http://sun. For example:
# zpool online tank c1t1d0
As a last step. the fault tolerance of the pool might be compromised.Sun-Fire-T200. replace it. IMPACT: Fault tolerance of the pool may be compromised.0 EVENT-ID: a1fb66d0-cc51-cd14-a835-961c15696fcb DESC: The number of I/O errors associated with a ZFS device exceeded acceptable levels. Then. For example:
# zpool pool: state: status: status -x tank DEGRADED One or more devices could not be opened. For example:
# zpool status -x tank pool ’tank’ is healthy
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.sun. VER: 1. AUTO-RESPONSE: The device has been offlined and marked as faulted. action: Attach the missing device and online it using ’zpool online’. In either case.com/msg/ZFS-8000-FD for more information. REC-ACTION: Run ’zpool status -x’ and replace the bad device. CSN: -. HOSTNAME: neo2 SOURCE: zfs-diagnosis. the device just needs to be reattached to the system to restore normal operations.

at which point the disks will again be available. If a drive fails and it is no longer visible to the system. These events are relatively rare but common enough to cause potential data corruption in large or long-running systems. If the device is a network-attached drive. you must notify ZFS that the device is now available and ready to be reopened by using the zpool online command. or the system was rebooted as part of the attach procedure. then ZFS automatically rescans all devices when it tries to open the pool. it should be reattached to the system. If the device is a local disk. If the pool was degraded and the device was replaced while the system was running.
Determining the Type of Device Failure
The term damaged device is rather vague and can describe a number of possible situations:
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Bit rot – Over time. If the device is a USB device or other removable media. In this case. see “Bringing a Device Online” on page 93. the controller should be replaced. clear transient errors. though a large number of them might indicate a faulty drive. random events such as magnetic influences and cosmic rays can cause bits stored on disk to flip.
Replacing or Repairing a Damaged Device
This section describes how to determine device failure types.
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. the device should be treated as a damaged device. Follow the procedures in “Replacing or Repairing a Damaged Device” on page 274. For example:
# zpool online tank c0t1d0
For more information about bringing devices online.
Notifying ZFS of Device Availability
After a device is reattached to the system. These errors are typically transient. a controller might have failed such that the device is no longer visible to the system. connectivity to the network should be restored. Other problems can exist and depend on the type of hardware and its configuration. and replacing a device. If the pool was previously faulted.Replacing or Repairing a Damaged Device
Physically Reattaching a Device
Exactly how a missing device is reattached depends on the device in question. Misdirected reads or writes – Firmware bugs or hardware faults can cause reads or writes of entire blocks to reference the incorrect location on disk. ZFS might or might not automatically detect its availability.

com/msg/ZFS-8000-8A scrub: scrub completed after 0h0m with 2 errors on Tue Jul 13 11:08:37 2010 config: NAME STATE READ WRITE CKSUM tpool ONLINE 2 0 0 c1t1d0 ONLINE 2 0 0 c1t3d0 ONLINE 0 0 0 errors: Permanent errors have been detected in the following files: /tpool/words
The errors are divided into I/O errors and checksum errors. For example:
# zpool pool: state: status: status -v tpool tpool ONLINE One or more devices has experienced an error resulting in data corruption.
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Determining exactly what is wrong with a device can be a difficult process. The goal is to answer the following question: Is another error likely to occur on this device?
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. Temporary outage– A disk might become unavailable for a period of time. or any number of failures. If the log shows a large number of SCSI or Fibre Channel driver messages. see: http://www. both of which might indicate the possible failure type. These errors are typically permanent. including consistent I/O errors. action: Restore the file in question if possible. Offline device – If a device is offline. though local disks can experience temporary outages as well. then this situation probably indicates impending or complete device failure. If no syslog messages are generated. The first step is to examine the error counts in the zpool status output. then the damage is likely transient. The other source of information is the syslog system log. These errors might or might not be transient. If you are seeing a large number of errors. Bad or flaky hardware – This situation is a catch-all for the various problems that faulty hardware exhibits. faulty transports causing random corruption. then this situation probably indicates serious hardware problems.sun. Typical operation predicts a very small number of errors (just a few over long periods of time). This situation is typically associated with network-attached devices.Replacing or Repairing a Damaged Device
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Administrator error – Administrators can unknowingly overwrite portions of a disk with bad data (such as copying /dev/zero over portions of the disk) that cause permanent corruption on disk. However. The administrator who placed the device in this state can determine if this assumption is accurate. it is assumed that the administrator placed the device in this state because it is faulty. an administrator error can also result in large error counts. Applications may be affected. These errors are always transient. causing I/Os to fail. Otherwise restore the entire pool from backup.

Errors that are persistent or severe enough to indicate potential hardware failure are considered fatal. To clear all errors associated with the virtual devices in a pool. After determination is made. see “Repairing Damaged Data” on page 283. Even if the device errors are considered transient. use the zpool clear command. they still might have caused uncorrectable data errors within the pool. the appropriate action can be taken. Whether the device can be replaced depends on the configuration. For more information about repairing data errors. For example:
# zpool clear tank c1t1d0
This syntax clears any device errors and clears any data error counts associated with the device. see “Clearing Storage Pool Device Errors” on page 94.Replacing or Repairing a Damaged Device
Errors that happen only once are considered transient and do not indicate potential failure. the device must be replaced. even if the underlying device is deemed healthy or otherwise repaired. These repair procedures are described in the next sections. To clear error counters for RAID-Z or mirrored devices.
Replacing a Device in a ZFS Storage Pool
If device damage is permanent or future permanent damage is likely. in that they are unlikely to affect the future health of the device.
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“Determining If a Device Can Be Replaced” on page 277 “Devices That Cannot be Replaced” on page 277 “Replacing a Device in a ZFS Storage Pool” on page 278 “Viewing Resilvering Status” on page 281
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. they can be safely cleared to indicate that no fatal error occurred. the administrator.
Clearing Transient Errors
If the device errors are deemed transient. and so much must be done manually by you. use the following syntax:
# zpool clear tank
For more information about clearing pool errors. The act of determining the type of error is beyond the scope of any automated software currently available with ZFS. and to clear any data error counts associated with the pool. These errors require special repair procedures. Either clear the transient errors or replace the device due to fatal errors.

If the device is damaged but otherwise online. For example. For more information about restoring an entire pool.
raidz c1t0d0 c2t0d0 c3t0d0 c4t0d0 FAULTED ONLINE FAULTED FAULTED ONLINE
In the following configuration. no good data with which to heal the damaged device exists. if two disks in a four-way mirror are faulted. sufficient replicas from which to retrieve good data must exist. then the device cannot be safely replaced. though no self-healing of data can take place because no good replica is available. if two disks in a four-way RAID-Z (raidz1) virtual device are faulted. unless sufficient replicas with good data exist. then either disk can be replaced because healthy replicas are available. and then to restore your data from a backup copy. then no replacement can be performed because the pool itself is faulted. it can be replaced as long as the pool is not in the FAULTED state. the c1t1d0 disk can be replaced. see “Repairing ZFS Storage Pool-Wide Damage” on page 286. However.
Devices That Cannot be Replaced
If the loss of a device causes the pool to become faulted or the device contains too many data errors in a non-redundant configuration. either top-level disk can be replaced. then neither disk can be replaced because insufficient replicas from which to retrieve data exist. c1t0d0:
mirror c1t0d0 c1t1d0 DEGRADED ONLINE FAULTED
The c1t0d0 disk can also be replaced. the only option is to destroy the pool and re-create the configuration. Without sufficient redundancy. any corrupted data on the device is copied to the new device. neither faulted disk can be replaced.
c1t0d0 c1t1d0 ONLINE ONLINE
If either disk is faulted.
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. and any data in the pool is copied from the healthy replica. The ONLINE disks cannot be replaced either because the pool itself is faulted.Replacing or Repairing a Damaged Device
Determining If a Device Can Be Replaced
If the device to be replaced is part of a redundant configuration. though any bad data present on the disk is copied to the new disk. In this case. However. In the following configuration. In the following configuration.

see “Replacing Devices in a Storage Pool” on page 94. If you have already removed the device and replaced it with a new device in the same location. The basic steps follow:
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Take offline the disk (c1t3d0)to be replaced. For example:
# zpool replace tank c1t1d0
This command takes an unformatted disk. use the zpool replace command to replace the device. Reconfigure the disk (c1t3d0). formats it appropriately. For more information about the zpool replace command. but the pool will continue to be available. and then resilvers data from the rest of the configuration. Bring the new disk (c1t3d0) online. it detaches the damaged device from the configuration.Replacing or Repairing a Damaged Device
Replacing a Device in a ZFS Storage Pool
After you have determined that a device can be replaced. then you must unconfigure the disk before you attempt to replace it. Run the zpool replace command to replace the disk (c1t3d0). If you are replacing the damaged device with different device. Use the cfgadm command to identify the disk (c1t3d0) to be unconfigured and unconfigure it. at which point the device can be removed from the system. use syntax similar to the following:
# zpool replace tank c1t1d0 c2t0d0
This command migrates data to the new device from the damaged device or from other devices in the pool if it is in a redundant configuration. use the single device form of the command. To replace the disk c1t3d0 with a new disk at the same location (c1t3d0). When the command is finished. Ensure that the blue Ready to Remove LED is illuminated before you physically remove the faulted drive. You cannot unconfigure a disk that is currently being used. Physically replace the disk (c1t3d0).
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EXAMPLE 11–1
Replacing a Device in a ZFS Storage Pool
The following example shows how to replace a device (c1t3d0) in a mirrored storage pool tank on Oracle's Sun Fire x4500 system. The pool will be degraded with the offline disk in this mirrored configuration.

When an entire disk is replaced.34% done
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Resilver completion message.64% done config: NAME tank mirror-0 replacing-0 c1t0d0 c2t0d0 c1t1d0 STATE ONLINE ONLINE ONLINE ONLINE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (resilvering) 0 0 0 # zpool pool: state: status:
In this example. Resilvering is interruptible and safe. scan: resilver in progress since Mon Jun 7 10:49:20 2010 54. Traditional file systems resilver data at the block level.3G scanned out of 16. For example:
status tank tank ONLINE One or more devices is currently being resilvered. 82.46M/s.3G resilvered. the resilvering process resumes exactly where it left off.Replacing or Repairing a Damaged Device
scan: resilver in progress since Mon Jun 7 09:17:27 2010 13. it can perform resilvering in a much more powerful and controlled manner. 0h0m to go 54. action: Wait for the resilver to complete. The pool will continue to function.
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To view the resilvering process.2G at 18. use the zpool status command. The purpose of this device is solely to display the resilvering progress and to identify which device is being replaced. nor is it possible for you to create a pool by using it. Replacing a 500-GB disk can take seconds if a pool has only a few gigabytes of used disk space.6M scanned out of 222M at 5. Note that any pool currently undergoing resilvering is placed in the ONLINE or DEGRADED state because the pool cannot provide the desired level of redundancy until the resilvering process is completed. If the system loses power or is rebooted. This event is observed in the status output by the presence of the replacing virtual device in the configuration. the disk c1t0d0 is being replaced by c2t0d0.2G in 0h16m with 0 errors on Mon Jun 7 09:34:21 2010
Resilver completion messages persist across system reboots. The two main advantages of this feature are as follows:
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ZFS only resilvers the minimum amount of necessary data. Resilvering proceeds as fast as possible.5M resilvered. In the case of a short outage (as opposed to a complete device replacement). without any need for manual intervention. the resilvering process takes time proportional to the amount of data used on disk. 0h2m to go 13. This device is not real.5M/s. 24. For example:
resilvered 16. possibly in a degraded state. though the I/O is always scheduled with a
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. Because ZFS eliminates the artificial layering of the volume manager. the entire disk can be resilvered in a matter of minutes or seconds.

see “Checking ZFS File System Integrity” on page 265.
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.
Repairing Damaged Data
The following sections describe how to identify the type of data corruption and how to repair the data. or an unlikely series of events conspired to corrupt multiple copies of a piece of data. redundancy. Nonetheless. This problem might result in a portion of the file or directory being inaccessible. and the original failed disk (c1t0d0) has been removed from the configuration.
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Data is verified during normal operations as well as through a scrubbing. complete. After the resilvering is completed. If this data is corrupted. if corruption occurred while a pool was degraded. the result is the same: The data is corrupted and therefore no longer accessible. Regardless of the source.Repairing Damaged Data
lower priority than user-requested I/O. data corruption can occur if a pool isn't redundant. the corruption is within a specific file or directory. the entire pool or portions of the dataset hierarchy will become unavailable. For example:
# zpool pool: state: scrub: config: status tank tank ONLINE resilver completed after 0h1m with 0 errors on Tue Feb 2 13:54:30 2010 NAME tank mirror-0 c2t0d0 c1t1d0 STATE ONLINE ONLINE ONLINE ONLINE READ WRITE CKSUM 0 0 0 0 0 0 0 0 0 377M resilvered 0 0 0
errors: No known data errors
The pool is once again ONLINE. if possible. or this problem might cause the object to be broken altogether.
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“Identifying the Type of Data Corruption” on page 284 “Repairing a Corrupted File or Directory” on page 285 “Repairing ZFS Storage Pool-Wide Damage” on page 286
ZFS uses checksums. Two basic types of data can be corrupted:
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Pool metadata – ZFS requires a certain amount of data to be parsed to open a pool and access datasets. The action taken depends on the type of data being corrupted and its relative value. and self-healing data to minimize the risk of data corruption. configuration. the configuration reverts to the new. For information about how to verify the integrity of pool data. to minimize impact on the system. Object data – In this case.

For example:
# zpool pool: state: status: status monkey monkey ONLINE One or more devices has experienced an error resulting in data corruption. If you determine that the errors are no longer present. the zpool status command shows only that corruption has occurred. this is the case. A complete scrub of the pool is guaranteed to examine every active block in the pool. but not where this corruption occurred. Otherwise restore the entire pool from backup. and you don't want to wait for a scrub to complete.Repairing Damaged Data
Identifying the Type of Data Corruption
By default.
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. http://www. Applications may be affected. For example:
# zpool pool: id: state: status: action: see: config: status -v morpheus morpheus 1422736890544688191 FAULTED The pool metadata is corrupted. Each error is not necessarily still present on the system. reset all errors in the pool by using the zpool online command. so the error log is reset whenever a scrub finishes. Under normal circumstances.sun. action: Restore the file in question if possible.sun. Certain temporary outages might result in data corruption that is automatically repaired after the outage ends.com/msg/ZFS-8000-72 morpheus c1t10d0 FAULTED ONLINE corrupted data
In the case of pool-wide corruption. the output is slightly different. the pool is placed into the FAULTED state because the pool cannot provide the required redundancy level. The pool cannot be imported due to damaged devices or data.com/msg/ZFS-8000-8A scrub: scrub completed after 0h0m with 8 errors on Tue Jul 13 13:17:32 2010 config: NAME monkey c1t1d0 c2t5d0 STATE ONLINE ONLINE ONLINE READ WRITE CKSUM 8 0 0 2 0 0 6 0 0
errors: 8 data errors. If the data corruption is in pool-wide metadata. use ’-v’ for a list
Each error indicates only that an error occurred at a given point in time. see: http://www.

the full path to the file is displayed.sun. If the damage is within a file data block.txt monkey/ghost/e.txt /monkey/bananas/b.Repairing Damaged Data
Repairing a Corrupted File or Directory
If a file or directory is corrupted. For example:
monkey/ghost/e. the system might still function. Applications may be affected. then the dataset name with no preceding slash (/). followed by the path within the dataset to the file. For example:
monkey/dnode:<0x0>
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.txt /monkey/ghost/boo/f. then the dataset name followed by the object's number is displayed. either due to an error or because the object doesn't have a real file path associated with it. see: http://www. Use the zpool status -v command to display a list of file names with persistent errors. Even so. thereby clearing the error from the system. is displayed. you must restore the affected data from backup. Otherwise restore the entire pool from backup.txt
The list of file names with persistent errors might be described as follows:
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If the full path to the file is found and the dataset is mounted. For example:
/monkey/a. If the data is valuable. as is the case for a dnode_t. For example:
# zpool pool: state: status: status -v monkey ONLINE One or more devices has experienced an error resulting in data corruption.txt /monkey/sub/dir/d.com/msg/ZFS-8000-8A scrub: scrub completed after 0h0m with 8 errors on Tue Jul 13 13:17:32 2010 config: NAME monkey c1t1d0 c2t5d0 STATE ONLINE ONLINE ONLINE READ WRITE CKSUM 8 0 0 2 0 0 6 0 0
errors: Permanent errors have been detected in the following files: /monkey/a. then the file can be safely removed. but the dataset is not mounted. action: Restore the file in question if possible.txt
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If the full path to the file is found. depending on the type of corruption.txt
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If the object number to a file path cannot be successfully translated. you might be able to recover from this corruption without restoring the entire pool. Any damage is effectively unrecoverable if no good copies of the data exist on the system.

You can use the zpool status command to review a damaged pool and the recommended recovery steps. A scrub of the pool is strongly recommended after recovery. Recovery is possible.
Repairing ZFS Storage Pool-Wide Damage
If the damage is in pool metadata and that damage prevents the pool from being opened or imported. you will see messages similar to the following:
# zpool import tpool cannot import ’tpool’: I/O error Recovery is possible. is displayed.sun. Returning the pool to its state as of Wed Jul 14 11:44:10 2010 should correct the problem. Approximately 5 seconds of data must be discarded. Recovery can be attempted by executing ’zpool import -F tpool’. Returning the pool to its state as of Wed Jul 14 11:44:10 2010 should correct the problem.Repairing Damaged Data
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If an object in the metaobject set (MOS) is corrupted. see: http://www. but will result in some data loss. These commands attempt to roll back the last few pool transactions to an operational state. A scrub of the pool is strongly recommended after recovery. irreversibly. For example:
# zpool pool: state: status: action: status tpool FAULTED The pool metadata is corrupted and the pool cannot be opened. followed by the object number. irreversibly. then the following options are available:
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Attempt to recover the pool by using the zpool clear -F command or the zpool import -F command. then a special tag of <metadata>. but will result in some data loss. Recovery can be attempted by executing ’zpool clear -F tpool’.
If the corruption is within a directory or a file's metadata.
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. You can safely move any file or directory to a less convenient location. allowing the original object to be restored in its place.com/msg/ZFS-8000-72 scrub: none requested config: NAME tpool c1t1d0 c1t3d0 STATE FAULTED ONLINE ONLINE READ WRITE CKSUM 0 0 1 corrupted data 0 0 2 0 0 4
The recovery process as described above is to use the following command:
# zpool clear -F tpool
If you attempt to import a damaged storage pool. Approximately 5 seconds of data must be discarded. the only choice is to move the file elsewhere.

see “Importing a Pool in Read-Only Mode” on page 121. preventing it from trying to
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. If the pool isn't in the zpool. keep a file describing the layout of the datasets and the various locally set properties somewhere safe. which means that such failures will cause a system to enter into a panic-reboot loop. use the zpool destroy -f command to destroy the pool. After the system is up. boot to the milestone none by using the -m milestone=none boot option.Repairing an Unbootable System
The recovery process as described above is to use the following command:
# zpool import -F tpool Pool tpool returned to its state as of Wed Jul 14 11:44:10 2010. you can reconstruct your complete configuration after destroying the pool. The location and contents of this file are private and are subject to change. If the system becomes unbootable.cache file to another location. the problem is discovered when the system is booted. The mechanism you use varies widely depending on the pool configuration and backup strategy. For example:
# zpool import -o readonly=on tpool
For more information about importing a pool read-only. To recover from this situation. see “Importing a Pool With a Missing Log Device” on page 119. each pool must be opened. As part of the boot process. Also. ZFS maintains an internal cache of available pools and their configurations in /etc/zfs/zpool.
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Repairing an Unbootable System
ZFS is designed to be robust and stable despite errors. This method allows you to import the pool so that you can access the data. you must restore the pool and all its data from a backup copy. save the configuration as displayed by the zpool status command so that you can recreate it after the pool is destroyed. software bugs or certain unexpected problems might cause the system to panic when a pool is accessed. The data can then be populated by using whatever backup or restoration strategy you use.cache. and the damaged pool is reported in the zpool status command. Then.cache file. If the pool cannot be recovered by the pool recovery method described above. These actions cause ZFS to forget that any pools exist on the system.cache file. ZFS must be informed not to look for any pools on startup.
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You can import a pool with a missing log device by using the zpool import -m command.
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You can import a damaged pool in read-only mode. remount your root file system as writable and then rename or move the /etc/zfs/zpool. Discarded approximately 5 seconds of transactions
If the damaged pool is in the zpool. First. With the pool configuration and dataset layout. it won't successfully import or open and you'll see the damaged pool messages when you attempt to import the pool. as this information will become inaccessible if the pool is ever rendered inaccessible. Even so. For more information.

Repairing an Unbootable System

access the unhealthy pool causing the problem. You can then proceed to a normal system state by issuing the svcadm milestone all command. You can use a similar process when booting from an alternate root to perform repairs. After the system is up, you can attempt to import the pool by using the zpool import command. However, doing so will likely cause the same error that occurred during boot, because the command uses the same mechanism to access pools. If multiple pools exist on the system, do the following:
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Rename or move the zpool.cache file to another location as discussed in the preceding text. Determine which pool might have problems by using the fmdump -eV command to display the pools with reported fatal errors. Import the pools one by one, skipping the pools that are having problems, as described in the fmdump output.

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A P P E N D I X

Oracle Solaris ZFS Version Descriptions

A

A

This appendix describes available ZFS versions, features of each version, and the Solaris OS that provides the ZFS version and feature. The following sections are provided in this appendix:
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Overview of ZFS Versions
New ZFS pool and file system features are introduced and accessible by using a specific ZFS version that is available in Solaris releases. You can use the zpool upgrade or zfs upgrade to identify whether a pool or file system is at lower version than the currently running Solaris release provides. You can also use these commands to upgrade your pool and file system versions. For information about using the zpool upgrade and zfs upgrade commands, see “Upgrading ZFS File Systems (zfs upgrade)” on page 38 and “Upgrading ZFS Storage Pools” on page 123.

ZFS Pool Versions
The following table provides a list of ZFS pool versions that are available in the Solaris releases.
Version Oracle Solaris 11 Express Description